Interstate 66

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Interstate 66

I-66 highlighted in red
Route information
Length76.38 mi[1] (122.92 km)
NHSEntire route
RestrictionsNo trucks on Custis Memorial Parkway or Theodore Roosevelt Bridge
Major junctions
West end I-81 in Strasburg, VA
Major intersections
East end US 29 in Washington, D.C.
CountryUnited States
StatesVirginia, District of Columbia
CountiesVA: Frederick, Warren, Fauquier, Prince William, Fairfax, Arlington
DC: District of Columbia
Highway system
SR 65VA SR 67
US 50DC I-95

Interstate 66 (I-66) is an east–west Interstate Highway in the eastern United States. The highway runs from an interchange with I-81 near Middletown, Virginia, on its western end to an interchange with U.S. Route 29 (US 29) in Washington, D.C., at the eastern terminus. Much of the route parallels US 29 or State Route 55 (SR 55) in Virginia. I-66 has no physical or historical connection to the famous US 66, which was located in a different region of the United States.

The E Street Expressway is a spur from I-66 into the Foggy Bottom neighborhood of Washington, D.C.

Route description

  mi km
VA 74.8 120.54
DC 1.6 2.57
Total 76.4 123.11
Western terminus of I-66 at the interchange with I-81 in Middletown, Virginia


Interstate 81 to Dunn Loring

I-66 begins at a directional T interchange with I-81 near Middletown, Virginia. It heads east as a four-lane freeway and meets US 522/US 340 at a partial cloverleaf interchange. The two routes head south to Front Royal and north to Lake Frederick. I-66 continues east, paralleling SR 55 (John Marshall Highway) and meeting US 17 at a partial interchange with no access from southbound US 17 to westbound I-66. SR 55 also merges onto the freeway at this interchange, forming a three-way concurrency that ends near Marshall, with SR 55 leaving with U.S. Route 17 Business (US 17 Bus.) and US 17 leaving at the next exit.

Expanding to six lanes and continuing to parallel SR 55, I-66 enters the towns of Haymarket and Gainesville, reaching interchanges with US 15 (James Madison Highway) and US 29 (Lee Highway) in each town, respectively. The highway then heads to the south of the Manassas National Battlefield Park and to the north of the Bull Run Regional Park. The highway reaches another interchange with US 29 and passes to the north of Centreville and meets SR 28 (Sully Road) at an interchange with cloverleaf and stack elements to it. SR 28 heads north to Dulles International Airport and south to Manassas.

View west along I-66 in Oakton, with a Washington Metro train using the tracks in the median

The freeway then meets SR 286 (Fairfax County Parkway), US 50 (Lee Jackson Memorial Highway), and SR 123 (Chain Bridge Road) at a series of interchanges providing access to D.C. suburbs. The Orange Line and Silver Line of the Washington Metro begin to operate in the median here, as the highway reaches a large interchange with the I-495 (Capital Beltway).

I-66 has a tolled high-occupancy vehicle lane (HO/T lane) from US 15 to the Capital Beltway.

Dunn Loring to Theodore Roosevelt Bridge

The section of I-66 in Virginia east of the Capital Beltway is named the Custis Memorial Parkway,[2][3][4][5] a toll road with variable tolls during peak hours.[6] The road narrows to four lanes as it heads through affluent areas of Arlington. The parkway meets SR 7 (Leesburg Pike) at a full interchange. SR 267 (Dulles Toll Road) meets the parkway with an eastbound entrance and westbound exit. Continuing through neighborhoods, the route yet again meets US 29 at an incomplete interchange and continues east into Arlington, meeting SR 120 (Glebe Road) and continuing to Arlington County. It meets Spout Run Parkway and enters Rosslyn. The freeway turns southeast and runs in between US 29 as it approaches the Theodore Roosevelt Bridge, reaching another eastbound entrance and westbound exit as US 29 continues north on the Key Bridge. It then has a complex interchange with George Washington Parkway and SR 110 (Richmond Highway), providing access to Alexandria and the Pentagon, respectively. US 50 (Arlington Boulevard) merges onto the highway with a westbound exit and eastbound entrance and the two traverse the bridge.

The "Custis Memorial Parkway" name commemorates the Custis family, several of whose members (including Martha Dandridge Custis Washington, George Washington Parke Custis, Eleanor "Nelly" Parke Custis Lewis and Mary Anna Randolph Custis Lee) played prominent roles in Northern Virginia's history. Because of its terminus in the Shenandoah Valley, some early planning documents refer to I-66 as the "Shenandoah Freeway", although the name did not enter common use.[7]

Between the Capital Beltway and the Theodore Roosevelt Bridge, the eastbound (inbound) roadway is a high-occupancy toll (HOT) road from 5:30 to 9:30 am, and the westbound (outbound) roadway is an HOT road from 3:00 to 7:00 pm. E-ZPass is required for all vehicles except motorcycles, including Dulles Airport users. I-66 is free during those times for HOV-3+ drivers with an E-ZPass Flex and for motorcycles. Other drivers must pay a toll that can be almost $50 at peak times. Outside of these hours, I-66 is free for all drivers to use.[8]

District of Columbia

In Washington, D.C., the route quickly turns north, separating from US 50. The highway interchanges with the E Street Expressway spur before passing beneath Virginia Avenue in a short tunnel. After an indirect interchange with the Rock Creek and Potomac Parkway (via 27th Street), the highway terminates at a pair of ramps leading to the Whitehurst Freeway (US 29) and L Street. The portion of Interstate 66 within Washington, DC, is known as the Potomac River Freeway.

E Street Expressway

E Street Expressway

LocationWashington, D.C.
Length0.3 mi[9] (480 m)
View east along the E Street Expressway just east of I-66

The E Street Expressway is a spur of I-66 that begins at an interchange with the Interstate just north of the Roosevelt Bridge. It proceeds east, has an interchange with Virginia Avenue Northwest, and terminates at 20th Street Northwest. From there, traffic continues along E Street Northwest to 17th Street Northwest near the White House, the Old Executive Office Building, the George Washington University, and the Corcoran Gallery of Art. Westbound traffic from 17th Street takes a one-block segment of New York Avenue to the expressway entrance at 20th and E streets northwest. The expressway and the connecting portions of E Street and New York Avenue are part of the National Highway System.

In 1963, the construction of the E Street Expressway caused the demolition of multiple buildings of the Old Naval Observatory.[10]

Exit list

The entire route is in the Foggy Bottom neighborhood of Washington, D.C. All exits are unnumbered.


I-66 to US 29 south (Whitehurst Freeway) – Virginia
Western terminus
0.10.16Virginia Avenue / 23rd StreetEastbound exit only
Tunnel underneath Virginia Avenue
0.30.4820th Street / E Street eastEastern terminus; at-grade intersection
1.000 mi = 1.609 km; 1.000 km = 0.621 mi



2006 view of I-66 in Fairfax County outside of the Capital Beltway, with the Metrorail Orange Line in the median. The left lane was HOV, and the right shoulder was used as a travel lane during rush hour. This section was widened as part of the Transform 66 project.

I-66 was first proposed in 1956 shortly after Congress established the Highway Trust Fund as a highway to connect Strasburg, Virginia, in the Shenandoah Valley with Washington.[11][12]

During the planning stages, the Virginia Highway Department considered four possible locations for the highway inside the Beltway and, in 1959, settled on one that followed the Fairfax Drive–Bluemont Drive corridor between the Beltway and SR 120 (Glebe Road); and then the Washington and Old Dominion (W&OD) corridor between Glebe Road and Rosslyn in Arlington. The route west of 123 was determined earlier. Two other routes through Arlington neighborhoods and one along Arlington Boulevard were rejected due to cost or opposition.[13] I-66 was originally to connect to the Three Sisters Bridge, but, as that bridge was canceled, it was later designed to connect to the Potomac River Freeway via the Theodore Roosevelt Bridge.[14]

On December 16, 1961, the first piece of I-66, an 8.6-mile-long (13.8 km) section from US 29 at Gainesville to US 29 at Centreville was opened. A disconnected 3.3-mile-long (5.3 km) section near Delaplane in Fauquier County opened next in May 1962.

View east along I-66 at Scott Street in Arlington

In July 1962, the highway department bought the Rosslyn Spur of the W&OD for $900,000 (equivalent to $6.94 million in 2023[15]) and began clearing the way, such that, by 1965, all that remained was dirt and the shattered foundations of 200 homes cleared for the highway.[16][17][18] In February 1965, the state contracted to buy 30.5 miles (49.1 km) of the W&OD from Herndon to Alexandria for $3.5 million (equivalent to $25.8 million in 2023[15]) and the C&O petitioned the ICC to let them abandon it. The purchase would eliminate the need to build a grade separation for I-66 and would provide 1.5 miles (2.4 km) of right-of-way for the highway, saving the state millions.[19] The abandonment proceedings took more than three years, as customers of the railway and transit advocates fought to keep the railroad open and delayed work on the highway.[20] During that time, on November 10, 1967, the Washington Metropolitan Area Transit Authority (WMATA) announced that it had come to an agreement with the Highway Department that would give them a two-year option to buy a five-mile (8.0 km) stretch of the right-of-way from Glebe Road to the Beltway, where I-66 was to be built, and run mass transit on the median of it.[21] The W&OD ran its last train during the summer of 1968, thus clearing the way for construction to begin in Arlington.

While the state waited on the W&OD, work continued elsewhere. The Theodore Roosevelt Bridge opened on June 23, 1964, and, in November of that year, the section from Centerville to the Beltway opened. A 0.2-mile (0.32 km) extension from the Roosevelt Bridge to Rosslyn opened in October 1966.

After the Virginia Department of Transportation (VDOT; then known as the Virginia Department of Highways) took possession of the W&OD right-of-way in 1968, they began to run into opposition as the highway revolts of the late 1960s and early 1970s took hold. In 1970, the Arlington County Board requested new hearings, and opponents began to organize marches.[22][23] A significant delay was encountered when the Arlington Coalition on Transportation (ACT) filed a lawsuit in Federal District Court in 1971 opposing the Arlington portion of the project. The group objected to that urban segment due to concerns over air quality, noise, unwanted traffic congestion, wasteful spending, impacts on mass transit, and wasted energy by auto travel.[11] In 1972 the US Fourth Circuit Court of Appeals ruled in favor of ACT, technically blocking any construction. The US Supreme Court upheld the ruling in favor of ACT later that same year.[24]

Again, work continued elsewhere, and, in October 1971, the 6.6-mile-long (10.6 km) section from I-81 to US 340/US 522 north of Front Royal opened.

In July 1974, a final environmental impact statement (EIS) was submitted.[25] The EIS proposed an eight-lane Limited-access road from the Capital Beltway to the area near Spout Run Parkway.[25] Six lanes would branch off at the Parkway and cross the Potomac River via a proposed Three Sisters Bridge.[25] Another six lanes would branch off to the Theodore Roosevelt Bridge.[25] In November, a modified design was submitted, reducing the eight lanes to six. However, in 1975, VDOT disapproved the six-lane design.[25]

I-66 westbound access in Rosslyn, Arlington County

The parties then agreed on experts to conduct air quality and noise studies for VDOT, selecting the firm of ESL Incorporated, the expert hired originally by ACT. In 1976, United States Secretary of Transportation William Thaddeus Coleman Jr. intervened. On January 4, 1977, Coleman approved federal aid for a much narrower, four-lane limited access highway between the Capital Beltway and the Theodore Roosevelt Bridge.[25] As part of the deal, Virginia officials agreed to provide more than $100 million (equivalent to $393 million in 2023[15]) in construction work and funds to help build the Metro system, which has tracks down the I-66 median to a station at Vienna in Fairfax County; to build a multiuse trail from Rosslyn to Falls Church; and to limit rush-hour traffic mainly to car pools.[25][26][27] Three more lawsuits would follow, but work began on August 8, 1977, moments after US District Court Judge Owen R. Lewis denied an injunction sought by highway opponents.[28]

In the late 1970s and early 1980s, the highway's final miles were built. A 2.9-mile-long (4.7 km) section from Delaplane to US 17 east of Marshall was completed in two sections in 1978 and 1979. The 15.6-mile-long (25.1 km) section from US 340 to Delaplane was completed in August 1979. A 12-mile (19 km) section between US 17 in Marshall and US 15 in Haymarket opened in December 1979, with the gap between Haymarket and Gainesville closed on December 19, 1980.[29] On December 22, 1982, the final section of I-66 opened between the Capital Beltway and US 29 (Lee Highway) in Rosslyn, near the Virginia end of the Theodore Roosevelt Bridge.[25]

The Custis Trail, the trail along I-66 built between Rosslyn and Falls Church as a concession, opened in the summer of 1982, before the highway was complete. SR 267 (Dulles Access Road) between I-66 and the airport opened in 1984.[25] The Metrorail in the median of I-66 between Ballston and Vienna, another concession, opened on June 7, 1986.

After opening, the restrictions on use began to loosen. In 1983, Virginia dropped the HOV requirement from 4 to 3 and then from 3 to 2 in 1994. In 1992, motorcycles were allowed.[25]

On October 9, 1999, Public Law 106-69 transferred from the federal government to the Commonwealth of Virginia the authority for the operation, maintenance, and construction of I-66 between Rosslyn and the Capital Beltway.[30]

Because I-66 is the only Interstate Highway traveling west from Washington, D.C., into Northern Virginia, traffic on the road is often extremely heavy. For decades, there has been talk of widening I-66 from two to three lanes each way inside the Capital Beltway (I-495) through Arlington County, Virginia, although many Arlington residents are adamantly opposed to this plan. In 2004–2005, Virginia studied options for widening the highway inside the Beltway, including the prospect of implementing a one-lane-plus-shoulder extension on westbound I-66 within the Beltway (in an attempt to reduce congestion for people commuting away from D.C.).[31] They later settled on three planned "spot improvements" meant to ease traffic congestion on westbound I-66 inside the Capital Beltway. The first "improvement", a 1.9-mile (3.1 km) zone between Fairfax Drive and Sycamore Street, started in summer 2010 and was finished in December 2011. For this project, the entrance ramp acceleration lane and the exit ramp deceleration lanes were lengthened to form a continuous lane between both ramps. The 12-foot (3.7 m) shoulder lane can carry emergency vehicles and can be used in emergency situations.[32][33] The second one widened 1.675 miles (2.696 km) between the Washington Boulevard onramp and the ramp to the Dulles Access Road. Work on it began in 2013 and finished in 2015.[34] The third project, between Lee Highway/Spout Run and Glebe Road, is scheduled for completion in 2020.[35][needs update]

In Gainesville, Virginia, the Gainesville Interchange Project upgraded the interchange between US 29 and I-66 for those and many other roads due to rapid development and accompanying heavy traffic in the Gainesville and Haymarket area. I-66's overpasses were reconstructed to accommodate nine lanes (six general purpose, two HOV, and one collector–distributor eastbound) and lengthened for the expansion of US 29 to six lanes. These alterations were completed in June 2010. In 2014–2015, US 29 was largely grade-separated in the area, including an interchange at its current intersection with SR 619 (Linton Hall Road). The project began in 2004 and finished in 2015.[36]

Transform 66

I-66 eastbound past the US 29 interchange in Centreville

The Virginia Department of Transportation announced its public-private partnership with the Virginia Department of Rail and Public Transportation, and the private partner, I-66 Express Mobility Partners, with an estimating $3.7 billion dollars for transportation/road improvements along the I-66 corridor. The project, known as Transform 66, opened to traffic in November 2022 and the HOV rule changed from HOV-2+ to HOV-3+ in early December 2022.[37]


In 2015, the VDOT Transportation planning board added I-66 HOT lanes to their list of priority projects for the I-66 corridor.[38] The projects have sparked opposition between residents and community businesses over the direction of this region's future infrastructure planning. The VDOT established a "Transform 66" website on regional traffic issues. Residents living within the I-66 corridor have set up "Transform 66 Wisely", a website describing local community impacts that the VDOT projects may cause. In contrast, local business groups and Chambers of Commerce located near the affected areas have voiced support for transportation improvements in the I-66 region.[39]

Residents along the I-66 corridor, such as in Arlington County, have resisted I-66 widening proposals for many years.[40] The local Stenwood Elementary School would lose its attached field, leaving it with blacktop-only recess space.[41] In an April 16, 2015, letter to the Virginia Secretary of Transportation, members of the 1st, 8th, 10th, and 11th districts of Congress wrote that VDOT research noted that, during peak hours, 35 percent of eastbound cars and 50 percent of westbound cars are HOV violators.

Future federal steps for VDOT include National Environmental Policy Act (NEPA) review, obligation of federal funds, certification that the conversion to tolled facilities will not "degrade" the existing facility, and potential federal loan guarantee. The Virginia Commonwealth Transportation Board (CTB) is responsible for overseeing VDOT and allocating highway funding to specific projects. The board has 18 members appointed by the Governor,[42] includes the Virginia Secretary of Transportation, Aubrey Layne, and is the group that will be making the final decision and allocating funding for VDOT's plans for I-66.

In 2016, VDOT announced that it was planning to add express lanes and multimodal transportation improvements to I-66 outside the Beltway (the "Transform 66 Outside the Beltway" improvement project). A decision was also made to move forward with widening I-66 eastbound and make multimodal improvements from the Dulles Airport connector to Ballston (the "Transform 66 Inside the Beltway" improvement project).[43]

VDOT also announced during 2016 that it would initiate on I-66 a dynamic tolling system in the peak travel directions during rush hours. On December 4, 2017, VDOT converted 10 miles (16 km) of I-66 between US 29 in Rosslyn and the Capital Beltway to an HOV variable congestion pricing tolling system. The system permits solo drivers to use I-66 during peak travel hours in the appropriate direction if they pay a toll.[44]

VDOT designed the price of toll to keep traffic moving at a minimum of 45 mph (72 km/h) and to increase the capacity of the road. Carpools and vanpools (with three or more people),[needs update] transit, on-duty law enforcement and first responders will not pay a toll.[45] Prices ranged up to $47 for solo drivers, but the average speed during the morning rush hour was 57 mph (92 km/h) versus 37 mph (60 km/h) a year before.[46][47]

In 2017, construction began on the "Transform 66 Outside the Beltway" improvement project.[48] The project added 22.5 miles (36.2 km) of new dynamically-tolled express lanes alongside I-66 from I-495 to University Boulevard in Gainesville. It also built new park and ride facilities, interchange improvements and 11 miles (18 km) of expanded multi-use trail. The project was completed in November 2022.[49]

View "west" (actually south) at the eastern terminus of I-66 at US 29 in Washington, D.C.

Construction on widening eastbound I-66 as part of the "Transform 66 Inside the Beltway" improvement project began in June 2018 and was completed in 2020. The project added a travel lane on eastbound I-66 between the Dulles Access Road and Fairfax Drive (exit 71) in Ballston, and provided a new ramp-to-ramp direct access connection from eastbound I-66 to the West Falls Church station at the SR 7 interchange and provided a new bridge for the W&OD Trail over US 29.[45][needs update]

VDOT completed in August 2018 a diverging diamond interchange in Haymarket at the interchange of I-66 with US 15.[50]

District of Columbia

The Potomac River Freeway (I-66) in Washington, D.C.
A map of I-66, showing cities and interchanges with I-81 and I-495

In Washington D.C., I-66 was planned to extend east of its current terminus along the North Leg of the Inner Loop freeway. I-66 would have also met the eastern terminus of the planned I-266 at US 29, and the western terminus of I-695 (South Leg Freeway) at US 50; I-266 would have been a parallel route to I-66, providing more direct access to the North Leg from points west, while I-695 would have been an inner-city connector between I-66 and I-95.

The final plans for the North Leg Freeway, as published in 1971, outlined a 1.5-mile (2.4 km) six-lane tunnel beneath K Street, between I-266/US 29 and New York Avenue, where the North Leg would emerge from the tunnel and join with the Center Leg Freeway (formerly I-95, now I-395); the two routes would run concurrently for 0.75 miles (1.21 km) before reaching the Union Station interchange, where I-66 was planned to terminate. Despite the plan to route the North Leg in a tunnel beneath K Street, the intense opposition to previous, scrapped alignments for the D.C. freeway network, which included previous alignments for the North Leg Freeway, led to the mass cancelation of all unbuilt D.C. freeways in 1977, resulting in the truncation of I-66 at US 29.

Exit list

All exits in the District of Columbia are unnumbered.

State/districtCountyLocationmi[51]kmOld exitNew exitDestinationsNotes
VirginiaFrederick0.000.001 I-81 – Roanoke, WinchesterWestern terminus; signed as exits 1A (south) and 1B (north); exit 300 on I-81; tri-stack interchange
WarrenFront Royal6.410.326 US 340 / US 522 – Winchester, Front Royal
SR 79 to SR 55 – Linden, Front Royal
FauquierMarkham18.529.8418 SR 688 – Markham

US 17 north / SR 55 west / SR 731 – Delaplane, Paris
Western terminus of US 17 / SR 55 concurrency
SR 55 east (US 17 Bus. south) / SR 647 – Marshall
Eastern terminus of SR 55 concurrency; former SR 242 south

US 17 south / US 17 Bus. north – Marshall, Warrenton, Fredericksburg
Eastern terminus of US 17 concurrency
31.350.4831 SR 245 – The Plains, Old Tavern
Prince WilliamHaymarket40.565.2940 US 15 – Haymarket, LeesburgDiverging diamond interchange
Gainesville43.169.41043 US 29 – Gainesville, WarrentonSigned as exits 43A (south) and 43B (north)
SR 234 south (Prince William Parkway) – Manassas, Dumfries
Western terminus of SR 234 concurrency

SR 234 north / SR 234 Bus. south – Manassas, Manassas National Battlefield Park
Eastern terminus of SR 234 concurrency; signed as exits 47A (south) and 47B (north) westbound
48.878.5Rest area

US 29 to SR 28 south – Centreville
CentrevilleChantilly line53.285.61453B
SR 28 north – Dulles Airport
Signed as exit 53 eastbound; no westbound entrance
SR 28 south – Centreville
Westbound exit and eastbound entrance
Fair Lakes54.988.4Stringfellow Road (SR 645)Westbound exit or eastbound entrance via 24/7 HOT ramp[52]
55.990.01555 SR 286 (Fairfax County Parkway) – Springfield, Reston, HerndonSigned as exits 55A (south) and 55B (north)
Fair Oaks57.191.9Monument Drive (SR 7969)24/7 HOT exit and entrance both directions[52]
58.193.51657 US 50 – Fair Oaks, Winchester, FairfaxSigned as exits 57A (east) and 57B (west)
Oakton60.196.71760 SR 123 – Fairfax, Vienna
61.699.117A62 Vienna/Fairfax-GMU StationAccessible via C/D lanes
OaktonMerrifield line62.5100.6 SR 243 (Nutley Street) – Vienna, Fairfax
Dunn LoringMerrifield
Idylwood tripoint
I-495 south – Richmond, Alexandria
Signed as exit 64 westbound; exit 49 on I-495
I-495 north – Tysons Corner, Baltimore
Eastbound exit and westbound entrance; exit 49 on I-495

I-495 Express – Richmond, Baltimore
Eastbound exit and westbound entrance
IdylwoodToll gantry (non-HOV3+ vehicles, peak-direction only)[8]
Pimmit HillsIdylwood line66.0106.21966 SR 7 (Leesburg Pike) – Tysons Corner, Falls ChurchSigned as exits 66A (east) and 66B (west) westbound; serves West Falls Church station

SR 267 west to I-495 north – Dulles Airport, Baltimore
Westbound exit and eastbound entrance; eastern terminus of SR 267
WesthamptonToll gantry (non-HOV3+ vehicles, peak-direction only)[8]
ArlingtonEast Falls Church67.8109.12168Westmoreland StreetEastbound exit only
68.4110.12269 US 29 / SR 237 (Washington Boulevard / Lee Highway)Eastbound exit and westbound entrance
2369Sycamore Street – Falls ChurchWestbound exit and eastbound entrance; serves East Falls Church station
BluemontToll gantry (non-HOV3+ vehicles, peak-direction only)[8]
Ballston70.5113.52471 SR 120 (Glebe Road) / SR 237 (Fairfax Drive)Serves Ballston–MU station
CherrydaleToll gantry (non-HOV3+ vehicles, peak-direction only)[8]
Maywood72.1116.02572 US 29 (Lee Highway) / Spout Run ParkwayEastbound exit and westbound entrance
Rosslyn73.1117.62673 US 29 (Lee Highway) – Rosslyn, Key Bridge
SR 110 south – Pentagon, Alexandria
Eastbound exit and westbound entrance
VirginiaD.C. lineArlingtonWashington line74.8
Theodore Roosevelt Bridge over the Potomac River
US 50 west (Arlington Boulevard) / George Washington Parkway north
Western terminus of US 50 concurrency; westbound exit and eastbound entrance
District of ColumbiaWashington0.50.80Independence AvenueEastbound exit only

US 50 east (Constitution Avenue) – Downtown
Eastern terminus of US 50 concurrency; eastbound exit and westbound entrance
0.71.1E Street Expressway eastWestern terminus of the E Street Expressway
0.81.3Kennedy CenterWestbound entrance only
0.91.4Independence Avenue / Maine AvenueWestbound exit and eastbound entrance
1.21.9Rock Creek ParkwayEastbound exit and westbound entrance
1.42.3Pennsylvania AvenueEastbound exit only
1.62.6Whitehurst Freeway (US 29 south) to Canal RoadEastern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

Auxiliary routes

Interstate 266

LocationArlington, VirginiaWashington, D.C.
Length1.79 mi (2.88 km)
NHSEntire route

Interstate 266 (I-266) was a proposed loop route of I-66 between Washington, D.C., and Arlington County, Virginia. D.C. officials proposed designating the route Interstate 66N, a move opposed by AASHTO. In Virginia, I-266 would have split off from I-66 just east of the present SR 124 (Spout Run Parkway) exit. From there, it would have followed an expanded Spout Run Parkway, crossed the George Washington Memorial Parkway, and crossed the Potomac River across a new bridge that would have been called the Three Sisters Bridge. Upon entering D.C., it would have followed Canal Road and an expanded US 29 (Whitehurst Freeway) to rejoin I/66 at K Street. I-266 was canceled in 1972 in the face of community opposition during Washington's "freeway revolts".


  1. ^ "Table 1: Main Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways as of October 31, 2002". Route Log and Finder List. Federal Highway Administration. Archived from the original on September 8, 2012.
  2. ^ "Arlington Virginia List of State Roads". Department of Environmental Services. Government of Arlington County, Virginia. July 14, 2009. Archived from the original on March 4, 2006. Retrieved 2010-08-23. I-66 Custis Memorial Parkway
  3. ^ "State Roads". Transportation. Government of Arlington County, Virginia. Archived from the original on April 12, 2014. Retrieved December 27, 2020. Interstate 66: Custis Memorial Parkway
  4. ^ "I-66". The Virginia Highways Project. Archived from the original on June 13, 2015. Retrieved December 27, 2020. Legislative names: Custis Memorial Parkway, I-495 to DC (since 1-21-82)
  5. ^ Levey, Bob (November 5, 1981). "An Honor That Nellie Custis Doesn't Deserve". The Washington Post. Retrieved December 27, 2020. Ain't no sense in trying to turn it around," said D. D. Harris, an engineer for the Virginia Highway Department. "Arlington County and Fairfax County agreed a year ago to call it the Custis Memorial Parkway. We've even ordered the signs for the entrances.
    "The only thing that hasn't been done is for final approval to be granted. But that's just dotting I's and crossing T's. It's settled. This is no time to be drumming up business.
  6. ^ "66 Express Lanes - Inside the Beltway :: About the Lanes". Retrieved 2021-01-09.
  7. ^ "Department of Planning & Zoning – Planning Zoning" (PDF). Archived (PDF) from the original on February 8, 2017. Retrieved May 3, 2018.
  8. ^ a b c d e "66 Express Lanes - Inside the Beltway :: Using the Lanes". Retrieved 2019-09-02.
  9. ^ a b Google (January 31, 2020). "E Street Expressway" (Map). Google Maps. Google. Retrieved January 31, 2020.
  10. ^ Harden, Victoria A.; Lyons, Michele (2018-02-27). "NIH's Early Homes". The NIH Catalyst. Retrieved 2020-09-28.
  11. ^ a b Lynton, Stephen (22 December 1982). "A Long Road Bitter Fight Against I-66 Now History". The Washington Post. Retrieved 11 October 2018.
  12. ^ Guinn, Muriel (18 June 1958). "Approach to Airport Urged for Highway 66". The Washington Post.
  13. ^ Lawson, Jack (20 February 1959). "Arlington Corridor Chosen For Interstate Highway 66". The Washington Post.
  14. ^ Ladner, George (19 September 1964). "Committee Will Await Public Reaction Before Deciding on Site for Bridge". The Washington Post.
  15. ^ a b c Johnston, Louis; Williamson, Samuel H. (2023). "What Was the U.S. GDP Then?". MeasuringWorth. Retrieved November 30, 2023. United States Gross Domestic Product deflator figures follow the MeasuringWorth series.
  16. ^ "Rail Spur Quiet for While: But the Old W&OD Route Soon Will Hum With Autos". The Washington Post. 16 November 1964.
  17. ^ "W&OD Rail Spur Bought by State". The Washington Post. 10 July 1962.
  18. ^ Cheek, Leslie (15 October 1965). "I-66 in Arlington Planned As Model of Road Beauty". The Washington Post.
  19. ^ "ICC Examiner Favors Death of W&OD Line". The Washington Post. 8 March 1966.
  20. ^ "Ailing Va. Railroad Allowed to Quit in '68". The Washington Post. 25 January 1968.
  21. ^ Corrigen, Richard (2 November 1967). "WMATA Agrees On Rail Bed Route". The Washington Post.
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External links

Browse numbered routes
SR 65VA SR 67
US 50DC I-95