Interstate 25 in Colorado

This article is about the section of Interstate 25 in Colorado. For the entire route, see Interstate 25.

"U.S. Route 87 in Colorado" redirects here. For the entire length of the highway, see U.S. Route 87.

Interstate 25
U.S. Route 87
I-25 and US 87 highlighted in red
Route information
Maintained by CDOT
Length	298.87 mi (480.98 km)
Existed	1958–present
NHS	Entire route
Major junctions
South end	I-25 / US 85 / US 87 near Trinidad
Major intersections	US 160 at Trinidad and Walsenburg US 50 in Pueblo US 24 in Colorado Springs SH 470 / E-470 in Lone Tree I-225 in Denver US 285 in Denver US 40 / US 287 in Denver I-70 / US 6 / US 85 in Denver I-76 in North Washington I-270 / US 36 in Welby E-470 / Northwest Parkway in Broomfield US 34 in Loveland
North end	I-25 / US 87 near Wellington
Location
Country	United States
State	Colorado
Counties	Las Animas, Huerfano, Pueblo, El Paso, Douglas, Arapahoe, Denver, Adams, Broomfield, Weld, Larimer
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future Colorado State Highway System Interstate US State Scenic
← US 24 I-25 → SH 26
← SH 86 US 87 → SH 88

In the US state of Colorado, Interstate 25 (I-25) follows the north–south corridor through Colorado Springs and Denver. The highway enters the state from the north near Carr and exits the state near Starkville. The highway also runs through the cities of Fort Collins, Broomfield, Loveland, and Pueblo. The route is concurrent with U.S. Route 87 (US 87) through the entire length of the state. I-25 replaced US 87 and most of US 85 for through traffic.

Historical nicknames for this route have included the Valley Highway (through Denver), Monument Valley Highway (through Colorado Springs), and the Pueblo Freeway (through Pueblo). Within El Paso County, the route has been dedicated as the Ronald Reagan Highway. In Pueblo County, the route is called John F. Kennedy Memorial Highway.

I-25 is also considered to be part of the unofficial Pan-American Highway.

Route description

New Mexico state line to Pueblo

Northbound I-25 between Colorado Springs and Denver

Following the Santa Fe Trail from New Mexico, I-25 enters Colorado while concurrent with US 85 and US 87. It is a typical four-lane Interstate Highway, and its entire route in Colorado lies close to the east side of the Rocky Mountains. The route turns from north to west-northwest as I-25 serves Wootton. After leaving Wootton, I-25 turns back up north and bypasses near the east side of the Trinidad Lake State Park, home of the Trinidad Lake.

Trinidad, a city near the Trinidad Lake, is the first major city that lies along I-25. For the next 30 miles (48 km), I-25 continues north through the rural areas of Colorado until it reaches the small city of Walsenburg, where State Highway 25C (Interstate 25 Business, I-25 Bus.) junctions with US 160. I-25 then continues in a north-northwest direction until it bypasses the Orlando Reservoir, then turns north from there until it reaches Colorado City. In Colorado City, I-25 interchanges with the east end of the Frontier Pathways Scenic and Historic Byway (SH 165) at exit 74.

After leaving the city, I-25 follows in a north-northeast orientation until it reaches the St. Charles Reservoir just before entering the city of Pueblo, with the first exit within the southern city limits of Pueblo at exit 94. The Arkansas River in Pueblo serves as a feeder to the Lake Pueblo State Park, home of Pueblo Lake, which is located to the west of the western city limits of Pueblo.

Pueblo to Denver

I-25 northbound at the US 285/SH 30 interchange in Denver

After leaving Pueblo, I-25 continues up north with the Union Pacific Railroad line paralleling closely to the route on the right side after interchanging with Porter Draw at exit 106. By exit 119, the Fountain Creek joins along and travels parallel with I-25, and continues all the way to the Fountain Creek Regional Park in Widefield. I-25 gradually turns from a general north direction to the north-northwest and serves the census-designated place of Buttes at exit 122.

Cheyenne Mountain, as seen from I-25 near Fort Carson. Note the communications antennas at the summit, which are radio antennas for stations broadcasting in Colorado Springs.

As soon as US 85 leaves I-25 at exit 128, I-25 enters the city limits of Fountain. Basically, I-25 serves as the border between the western city limits of Fountain on the east side of I-25 and Fort Carson on the west side. Exit 132 (SH 16) serves the north side of the Fountain Creek Regional Park as well as the entrance to Fort Carson and connects to SH 21 (Powers Boulevard), the eastern bypass for the Colorado Springs metro area. By the time I-25 reaches exit 138, the route crosses into the city limits of Colorado Springs, where the stack interchange with US 24 at exit 139 serves the Evergreen Cemetery and Prospect Lake. I-25 turns west at exit 140, along with Fountain Creek, where it interchanges with US 85, US 87, and State Highway 25 Business (State Highway 25 Bus., I-25 Bus.). I-25, again, turns back north by exit 141. Swinging around the west side of downtown Colorado Springs at exit 142, and to the north of the city lies the Colorado College, and is served at exit 143 (Uintah Street). Continuing north and northeast, the highway intersects the north terminus of State Highway 25 Bus. and US 85. The Interstate leaves Colorado Springs between exits 153 and 156, where I-25 enters the United States Air Force Academy, going through the east side of the institution.

Map showing I-25 and nearby freeways and major highways in the Denver Metropolitan area

I-25 leaves El Paso County and enters Douglas County at Monument Hill, elevation 7,352 ft (2,241 m), north of Monument. I-25 then continues north through more rural and hilly areas east of the Rocky Mountains until reaching Castle Rock at exit 181. I-25 continues through rural and hilly portions of Douglas County until interchanging with E-470, the partial beltway of Denver as the toll road serves the Centennial Airport and the much larger Denver International Airport.

After entering Arapahoe County, I-25 cuts through the Denver Technological Center (DTC) between Dry Creek Road and Belleview Avenue (exits 196 and 199). I-25 enters Denver at the I-225 interchange, a spur that detours motorists to I-70 through Aurora, at exit 200. I-25 turns in a westerly direction between Evans Avenue (exit 203) and Colorado Boulevard (exit 204). University of Denver lies just to the south of the Interstate at exit 205. It then turns back north after exit 207. I-25 curves around the west side of downtown Denver, where it can be accessed by I-70 Bus. at exit 210. I-25 then interchanges with I-70 at exit 214 right before leaving the City and County of Denver.

Denver to Wyoming state line

As I-25 leaves Denver, the route continues up north through unincorporated areas of Adams County and interchanges with I-76, I-270, and the Denver-Boulder Turnpike (US 36). Due to the complexity of this triangle-shaped interchange, it was known to be one of many malfunction junctions throughout the United States. Beyond that interchange, the Interstate enters the northern suburbs of the Denver metro area, such as Thornton and Northglenn, and at exit 220, I-25 slips its way through a narrow path between the Badding Reservoir (west side) and the Croke Lake (east side). Development begins to drop off after exit 223 (120th Avenue) after continuing north into Westminster and eastern Broomfield.

At exit 228, I-25 interchanges with the northern terminuses of E-470 and Northwest Parkway at a stack interchange, with the Larkridge Mall just to the north, served by 160th Avenue (SH 7). As I-25 continues north, it moves through rolling farm and grasslands with the Front Range and high mountains clearly visible to the west while passing through a medley of lakes and reservoirs. It stays generally flat with few moderate climbs in elevation, while also serving smaller cities like Dacono and Firestone to the east and Longmont to the west. This stretch of I-25 in northern Colorado also has large amounts of truck traffic between SH 7 and Wyoming. After some time in the rural farmlands, the Interstate enters the Fort Collins–Loveland metro area at exit 255, serving Loveland and Greeley to at exits 255 and 257, Windsor at exit 262, and continuing north to the Fort Collins city limits south of Harmony Road. The highway runs on the eastern side of Fort Collins, serving Colorado State University at exits 268 and 269 (which is also the most direct route to downtown). After exit 271, I-25 leaves Fort Collins and rolls into more rural grasslands past Wellington. Exits also become few and far between from here to Wyoming as well after gradually turning north-easterly toward the state line.

History

Ancestors and early freeways

Colorado had begun planning of a modern intercity route along the Front Range as early as 1944, well before the national movement toward an Interstate Highway system.

SH 1, an unpaved road, was completed between Denver and Pueblo by 1919. Average travel time between Pueblo and Colorado Springs on this route was approximately 2.5 hours (or a full 8.5 hours from Pueblo to Denver). This route was upgraded with the help of the federal government to become US 85 and US 87 by 1930, now paved in concrete and shortening the travel time between Pueblo and Colorado Springs to just one hour.

The cities of Denver (in 1948) and Pueblo (in 1949) were first to begin building multilane highway segments along the route of what would eventually become I-25. Construction follows an earlier segment of the Colorado and Southern Railway. Denver's segment was originally known as the Valley Highway and was completed by 1958. The city of Colorado Springs followed a similar theme with their Monument Valley Freeway, begun in 1955 and completed by July 1960. Pueblo's section—the Pueblo Freeway—was complete by July 1959.

Interstate completion

As the national Interstate Highway System began to take shape, actual "interstate" connections began to be made. Wyoming came first in 1964, building a nine-mile (14 km) link north to Cheyenne that was connected to Colorado's 17-mile (27 km) stretch.

Linking to New Mexico in the south would prove more problematic as the planned route had to stretch over Raton Pass, and its accompanying 1,800-foot (550 m) elevation change, within just 13 mi (21 km). Once again, US 85 and US 87 were used, but it had to be regraded in places to meet Interstate design guidelines. Construction began in 1960, with a link to the city of Trinidad completed by 1963. The Trinidad Segment (as CDOT now calls the Raton Pass span) was not fully completed until 1968.

The final segment of the Colorado portion of I-25, connecting the cities of Walsenburg and Trinidad, was completed during 1969. This meant that four lanes of high-speed, nonstop freeway were finally open for a full 305 miles (491 km) from New Mexico north to Wyoming.

Modern expansion

As both population and traffic increased in Colorado during the 1990s and 2000s, the Colorado Department of Transportation has planned and completed major improvements for the city corridors along I-25.

T-REX (Denver)

T-REX Logo

The first of these was Transportation Expansion (T-REX), which widened and expanded nearly 17 miles (27 km) of both I-25 and the I-225 bypass in the Denver Metropolitan Area as well as adding various pedestrian and aesthetic improvements. T-REX was also instrumental in expanding Denver's RTD light rail lines to connect outlying communities beyond the city and county of Denver, adding 19 miles (31 km) of new routes.

Starting in early 2004, the T-REX project was completed during 2006 at a cost of $1.67 billion, under its projected budget and two years ahead of its originally scheduled conclusion. It has been hailed as a "model for other cities to follow" and "ahead of the curve nationally" by federal transportation and transit authorities.

COSMIX (Colorado Springs)

COSMIX Logo

As T-REX began to wrap up, CDOT's next major effort began with Colorado Springs Metro Interstate Expansion (COSMIX). It could be argued that COSMIX was even more important to Colorado's interests than T-REX had been, since the Colorado Springs corridor of I-25 had seen immense growth over the past four decades, and experienced major choke points all along the 16-mile (26 km) corridor from exit 135 (Academy Blvd) in the south to exit 151 (Briargate Pkwy) in the north. Originally carrying around 8500 vehicles per day in 1960, usage of the former Monument Valley Freeway had grown to an average of 100,000 vehicles per day by 2005.

The major goals of COSMIX, which began in 2005 and was completed a year and four days ahead of schedule at the very end of December 2007, were a general expansion and widening of the corridor to three lanes in each direction throughout the city, as well as the reconstruction of two main interchanges (at Bijou Street near downtown Colorado Springs, and at Rockrimmon Boulevard and North Nevada Avenue in the city's growing north side). Originally estimated at $225 million, on delivery, COSMIX cost only $150 million, approximately $20 million of which involved land acquisition costs.

COSMIX was the first funded portion of a larger plan for I-25 improvements as detailed in an Environmental Assessment approved by CDOT and FHWA in 2004. A second phase resulted in the widening of the 12-mile (19 km) segment from Woodmen Road (exit 149) to Monument (exit 161) to six lanes and addition of auxiliary lanes at busy interchanges. The Air Force Academy interchange (exit 156) was reconfigured to include just one exit, instead of A/B, and features two new roundabouts for North Gate Boulevard. The widening and paving was completed in December 2014.

An EA-recommended improvement not included in COSMIX due to funding limitations was the reconstruction of the I-25 interchange at Cimarron Street (US 24 West). CDOT completed this project in late 2017.

Future

As of October 2020, a seven-mile (11 km) segment of I-25 through Pueblo is currently under construction. Enhancements include the widening of two bridges, noise wall installation, the softening of curves for better safety, and the addition of acceleration and deceleration lanes. The $69 million project has been completed.

There is much controversy surrounding the future of I-25 in northern Colorado (SH 7 in Broomfield to SH 14 in Fort Collins). Suggestions from adding toll lanes to general expansion to six lanes from the two lane bottleneck at SH 66 to SH 14 and adding multimodal transportation options have been discussed. The future of the highway remains in question as funding is limited, and agreement is limited as well. The I-25 corridor in Weld and Larimer counties is becoming increasingly heavy with traffic, and something will have to be done soon.

In Colorado Springs, SH 21 (Powers Blvd.) is currently getting extended past SH 83 to its official northern terminus at I-25. This project provides an easier bypass around the north end of the town and will also help connect Voyager Pkwy traffic to the Interstate. Powers Blvd. will eventually become a freeway bypass of the Colorado Springs metro area. The construction is in two phases, I-25 is involved in phase 1, where a new directional T-interchange (Y-interchange) will be built near exit 156 at N. Gate Blvd. between milemarkers 149 and 151. The interchange was completed in summer 2021.

The Gap is an 18-mile (29 km) stretch of I-25 from south of Castle Rock to Monument, in both Douglas and El Paso counties. It is the only four-lane section of I-25 between Colorado's two largest cities, Denver and Colorado Springs. Over the years, congestion, crashes, and delays have grown due to population growth and more people using the road. Efforts to improve these conditions are underway, and the project is completed with a cost of $350 million, with contributions from Douglas and El Paso counties, Pikes Peak Rural Transportation Authority and a federal INFRA grant.

Exit list

County	Location	mi	km	Exit	Destinations	Notes
Colorado–New Mexico line		0.000	0.000		I-25 south (US 85 south / US 87 east) / Santa Fe National Historic Trail – Raton	Continuation into New Mexico
				460	Truck weigh station	Northbound entrance extends into Colorado; exit number based on New Mexico mileage
Las Animas	​	2.134	3.434	2	Wootton
	​	5.597	9.007	6	Gallinas
	​	7.529	12.117	8	Spring Creek
	​	11.013	17.724	11	Starkville
	Trinidad	13.000	20.921	13A	Van Buren Street	Northbound exit and southbound entrance
		13.311	21.422	13B	SH 12 west (Main Street) / Highway of Legends National Scenic Byway / Santa Fe National Historic Trail
		13.906	22.380	14	Commercial Street
		14.859	23.913	15	US 160 east (Kit Carson Trail) / SH 239 north / Goddard Avenue	South end of US 160 overlap
	​	17.728	28.530	18	El Moro Road
	​	22.906	36.864	23	Hoehne Road
	​	26.858	43.224	27	Ludlow
	​	30.464	49.027	30	Aguilar Road
	​	34.090	54.863	34	I-25 BS west – Aguilar
Huerfano	​	40.485	65.154	41	Rugby Road
	​	41.930	67.480	42	Pryor
	Walsenburg	49.000	78.858	49	I-25 BL north / US 160 west – Walsenburg, Alamosa	North end of US 160 overlap
		50.054	80.554	50	SH 10 – La Junta
	​	52.321	84.202	52	SH 69 west – Gardner, Westcliffe	Southbound signed as I-25 Bus. to US 160
	​	55.000	88.514	55	Airport Road
	​	56.000	90.123	56	Redrock Road
	​	58.727	94.512	59	Butte Road
	​	60.084	96.696	60	Huerfano
	​	64.046	103.072	64	Lascar Road
	​	66.749	107.422	67	Apache
Pueblo	Colorado City	71.264	114.688	71	Graneros Road
		74.367	119.682	74	SH 165 west – Colorado City, Rye, San Isabel
	​	77.267	124.349	77	Abbey Road, Hatchet Ranch Road
	​	83.461	134.317	83	Brantzell
	​	86.938	139.913	87	Verde Road
	​	87.921	141.495	88	Burnt Mill Road
	​	90.625	145.847	91	Stem Beach
	Pueblo	94.769	152.516	94	SH 45 north (Pueblo Boulevard)
		95.403	153.536	95	Illinois Avenue	Southbound exit only
		95.901	154.338	96	Minnequa Avenue, Indiana Avenue	Southbound exit to Minnequa Ave., one block north of Indiana Ave.; Northbound exit to and entrance from Indiana Ave.; Southbound entrance from Aqua Ave., one block south of Indiana Ave.
		96.673	155.580	97A	McCulley Avenue to Northern Avenue
		97.447	156.826	97B	Abriendo Avenue
		97.691	157.218	98A	US 50 Bus. (Santa Fe Avenue)
		98.545	158.593	98B	To SH 96 / City Center Drive
		98.806	159.013	99A	To SH 96 / 6th Street	Southbound exit and northbound entrance (from Bradford Avenue)
		99.334	159.863	99B	13th Street	South end of US 50 Bus. overlap
		99.950	160.854	100A	US 50 east – La Junta, Pueblo Memorial Airport	South end of US 50 overlap; western terminus of US 50 Bus.
		100.681	162.030	100B	29th Street
		101.389	163.170	101	US 50 west / SH 47 east – Cañon City	North end of US 50 overlap
		102.160	164.411	102	Eagleridge Boulevard
		103.510	166.583	104	Dillon Drive, Drew Dix Parkway
	​	106.075	170.711	106	Porter Draw
	​	108.000	173.809	108	Purcell Boulevard – Pueblo West
	​	110.238	177.411	110	Pinon
	​	114.000	183.465	114	Young Hollow
	​	115.831	186.412	116	County Line Road
El Paso	​	118.843	191.259	119	Rancho Colorado Boulevard
	​	121.459	195.469	122	Pikes Peak International Raceway
	​	123.189	198.253	123	Clear Spring Ranch	Exit does not sign this destination
	​	124.564	200.466	125	Ray Nixon Road
	Fountain	127.860	205.771	128	US 85 north – Fountain	North end of US 85 overlap
		131.653	211.875	132	SH 16 east (Mesa Ridge Parkway) to SH 21 – Fort Carson Gate 20	Signed as exits 132A (SH 16) and 132B (Ft. Carson) southbound
	Stratmoor	135.262	217.683	135	South Academy Boulevard – Colorado Springs Airport
	Colorado Springs	137.752	221.690	138	Lake Avenue, Circle Drive
		138.742	223.284	139	US 24 east (Martin Luther King Jr. Bypass) – Limon	South end of US 24 overlap
		139.747– 139.869	224.901– 225.097	140	SH 115 south (Nevada Avenue, Tejon Street) / US 85 – Cañon City
		141.139	227.141	141	US 24 west (Cimarron Street) – Manitou Springs, Pikes Peak	North end of US 24 overlap
		141.849	228.284	142	Bijou Street – Downtown Colorado Springs
		142.832	229.866	143	Uintah Street
		143.520	230.973	144	Fontanero Street
		144.622	232.747	145	Fillmore Street	Diverging diamond interchange
		146.074	235.083	146	Garden of the Gods Road
		147.245– 148.030	236.968– 238.231	148	Nevada Avenue (US 85 south), Corporate Drive, Rockrimmon Boulevard	South end of US 85 overlap
		148.830	239.519	149	Woodmen Road
		150.303	241.889	150	North Academy Boulevard
		151.660	244.073	151	Briargate Parkway
		152.899	246.067	153	To SH 21 (Powers Boulevard) / Interquest Parkway – Black Forest
				155	Voyager Parkway	Future northern terminus for SH 21/Powers Blvd. Temporarily signed for Voyager Parkway
	Air Force Academy	155.930	250.945	156	North Gate Boulevard – North Entrance Air Force Academy
	​	158.199	254.597	158	Baptist Road
	Monument	160.763	258.723	161	SH 105 / 2nd Street – Monument, Palmer Lake
El Paso–Douglas county line	​	163.321	262.840	163	County Line Road – Palmer Lake
Douglas	​	167.464	269.507	167	Greenland
	​	171.820	276.517	172	Upper Lake Gulch Road
	​	172.307	277.301	173	Larkspur	Southbound exit and northbound entrance
	​	173.791	279.690	174	Tomah Road
	Castle Rock				Crystal Valley Parkway	Future interchange
		180.808	290.982	181	Plum Creek Parkway
		181.853	292.664	182	Wilcox Street, Wolfensberger Road
		184.212	296.460	184	US 85 north (Meadows Parkway) / SH 86 east (Founders Parkway)	North end of US 85 overlap
		185.097	297.885	185	Castle Rock Parkway to North Meadows Drive
	Castle Pines	186.935	300.843	187	Happy Canyon Road
		188.486	303.339	188	Castle Pines Parkway
	Lone Tree	192.096	309.149	192	RidgeGate Parkway
		192.990	310.587	193	Lincoln Avenue
		194.314	312.718	194	SH 470 west / E-470 east – Grand Junction, Limon	E-470 exit 1 westbound; SH-470 exit 26 eastbound; access to Denver International Airport
Douglas–Arapahoe county line	Lone Tree–Centennial line	195.130	314.031	195	County Line Road
Arapahoe	Centennial	196.141	315.658	196	Dry Creek Road
	Greenwood Village	197.188	317.343	197	SH 88 east (Arapahoe Road)	South end of SH 88 overlap
		198.292	319.120	198	Orchard Road
		199.384	320.877	199	SH 88 west (Belleview Avenue)	North end of SH 88 overlap
City and County of Denver		200.093	322.018	200	I-225 north to I-70 – Limon, Aurora	I-225 exits 1A-B southbound; tri-stack interchange; access to Denver International Airport
		201.578	324.408	201	US 285 south / SH 30 east (Hampden Avenue)
		202.640	326.117	202	Yale Avenue
		203.537	327.561	203	Evans Avenue
		204.037	328.366	204	SH 2 (Colorado Boulevard)
		205.057	330.007	205	University Boulevard
		205.919	331.395	206	Downing Street, Washington Street, Emerson Street	Downing St. not signed southbound
				207A	Lincoln Street, Broadway	Lincoln St. not signed southbound
				207B	Santa Fe Drive to SH 26 (Alameda Avenue)	Northbound exit and southbound entrance
					US 85 south (Santa Fe Drive)	South end of US 85 overlap; southbound exit and northbound entrance
		207.641– 207.990	334.166– 334.727	208	SH 26 (Alameda Avenue)	Southbound exit and northbound entrance; northbound access is via exit 207B
		209.210	336.691	209	US 6 west (6th Avenue) – Lakewood	South end of US 6 overlap; signed as exits 209A (east) and 209B (west)
		209.479	337.124	209C	8th Avenue
		210.310	338.461	210A	US 40 / US 287 (Colfax Avenue) – Downtown Denver
		210.415	338.630	210B	Auraria Parkway	Northbound exit and southbound entrance
		210.532	338.818	210C	17th Avenue	Northbound exit and entrance; southbound access is via exit 211
		211.109	339.747	211	23rd Avenue, 20th Avenue	20th Ave. not signed northbound
		211.464	340.318	212A-B	Speer Boulevard – Downtown Denver	Signed as exits 212A (south) and 212B (north)
		212.096	341.335	212C	20th Street
					I-25 HOV/toll lanes	South end of reversible HOV/toll lanes
				—	19th Street	Southbound exit and northbound entrance for HOV/toll lanes only
		212.769	342.419	213	Park Avenue, West 38th Avenue	Access to Coors Field
		213.625– 213.739	343.796– 343.980	214A	I-70 (US 6 east/US 85 north) – Limon, Grand Junction	North end of US 6/US 85 overlap; locally known as The Mousetrap; I-70 exit 274; access to Denver International Airport
		213.964	344.342	214B	48th Avenue	Southbound exit only
Adams	North Washington	215.244	346.402	215	58th Avenue
		216.301	348.103	216A	I-76 east – Fort Morgan	Northbound exit and southbound entrance; I-76 exit 5
	Welby	216.397– 216.779	348.257– 348.872	216B	SH 224 (70th Avenue) / I-76 west – Grand Junction	Signed as exit 216 southbound; SH 224 not signed southbound; I-76 exit 5
				—	SH 224 (70th Avenue)	Northbound exit and southbound right entrance for HOV/toll lanes only
		217.006	349.237	217	I-270 east / US 36 – Limon, Aurora, Westminster, Boulder	No access to I-270/US 36 east northbound; southbound signed as exits 217A (west) and 217B (east); I-270 exit 0 to I-25 north; access to Denver International Airport
				—	US 36 west – Boulder	Southbound right exit and northbound entrance for HOV/toll lanes only
					I-25 HOV/toll lanes	North end of reversible HOV/toll lanes
	Thornton	218.463	351.582	219	84th Avenue – Federal Heights
		219.815	353.758	220	Thornton Parkway
	Northglenn	221.027	355.708	221	104th Avenue	Former SH 44
		223.049	358.963	223	SH 128 west (120th Avenue)
	Westminster	225.000	362.102	225	136th Avenue
		226.085	363.849	226	144th Avenue
City and County of Broomfield		227.745	366.520	228	E-470 east / Northwest Parkway west – Limon, Broomfield	E-470/NW Pkwy. exit 47; access to Denver International Airport
		229.107	368.712	229	SH 7 – Lafayette, Brighton
Weld	​	232.094	373.519	232	Erie Parkway, Summit Boulevard – Erie, Dacono
	Dacono	235.114	378.379	235	SH 52 – Dacono, Frederick, Fort Lupton
	​	240.114	386.426	240	SH 119 west / Firestone Boulevard – Firestone, Longmont
	Mead	243.148	391.309	243	SH 66 – Longmont, Lyons
		245.217	394.639	245	County Road 34 Mead
	​	250.241	402.724	250	SH 56 west – Berthoud
	Johnstown	252.261	405.975	252	SH 60 east – Johnstown, Milliken
Larimer	​	254.216	409.121	254	To SH 60 west – Campion
	​	255.272	410.820	255	SH 402 west – Loveland
	Loveland	257.305	414.092	257	US 34 – Greeley, Loveland
		259.309	417.317	259	Crossroads Boulevard – Fort Collins-Loveland Airport
	Windsor	262.298	422.128	262	SH 392 – Windsor, Fort Collins
	Fort Collins	265.314	426.981	265	Harmony Road
		268.475	432.069	268	Prospect Road
		269.370– 269.570	433.509– 433.831	269	SH 14 – Fort Collins, Ault	Signed as exits 269A (east) and 269B (west)
		271.373	436.733	271	Mountain Vista Drive
	Wellington	277.884	447.211	278	SH 1 south – Wellington
	​	281.338	452.770	281	Owl Canyon Road
	​	287.550	462.767	288	Buckeye Road
Weld	​	292.583	470.867	293	CR 126 – Carr
	​	298.870	480.985		I-25 north / US 87 north – Cheyenne, Casper	Continuation into Wyoming
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Electronic toll collection       HOV only       Incomplete access       Unopened

Related routes

Auxiliary routes

Interstate 225
Location	Aurora
Length	12 mi (19 km)
NHS	Entire route

Main article: Interstate 225

In Colorado, I-25 has only one auxiliary route. Interstate 225 (I-225) is a 12-mile-long (19 km) spur route located within the Denver Metro Area. It runs from its parent highway from the Denver Tech Center to I-70 north of Aurora. It is an eastern bypass for travelers on I-25 looking to avoid Downtown Denver traffic and also provides direct connection to Denver International Airport for the southern suburbs of Denver. It is the only auxiliary route for I-25 as there are no other routes in Wyoming and New Mexico.

Business routes

Interstate 25 Business
Location	Aguilar, Walsenburg

Main article: Business routes of Interstate 25

Interstate 25 also has two active business routes within the state. In Aguilar, the town is connected to the freeway by Business Spur 25, which runs along Lynn Road and Walsenburg is served by Business Loop 25. There were three former routes that ran through Trinidad, Colorado Springs, and Castle Rock.

External links

• Colorado Department of Transportation (CDOT)
• COSMIX (CDOT project; website no longer being updated)
• South I-25 Corridor: Lincoln Avenue through Castle Rock (CDOT project)
• The North Forty (CDOT project)
• I-25 Trinidad (CDOT project)
• The New Pueblo Freeway (proposed CDOT project)