Interstate 29 in Iowa

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Interstate 29

I-29 highlighted in red
Route information
Maintained by Iowa DOT
Length151.826 mi[1] (244.340 km)
ExistedOctober 1, 1958 (1958-10-01)[2]–present
HistoryUnder construction 1958–1972
Lewis and Clark Trail
NHSEntire route
Major junctions
South end I-29 near Hamburg
Major intersections
North end I-29 at Sioux City
CountryUnited States
Highway system
Iowa 28 US 30

In the US state of Iowa, Interstate 29 (I-29) is a north–south Interstate Highway which closely parallels the Missouri River. I-29 enters Iowa from Missouri near Hamburg and heads to the north-northwest through the Omaha–Council Bluffs and the Sioux City areas. It exits the state by crossing the Big Sioux River into South Dakota. For its entire distance through the state, it runs on the flat land between the Missouri River and the Loess Hills.

I-29 was built in sections over a period of 15 years. When there was a shortage of male workers, female workers stepped in to build a 20-mile (32 km) section near Missouri Valley. Between Council Bluffs and Sioux City, I-29 replaced U.S. Highway 75 (US 75) as the major route in western Iowa. As a result of I-29's creation, US 75 south of Sioux City was relocated into Nebraska.

Route description

I-29 enters Iowa south of Hamburg. The Interstate heads northwest, where it meets Iowa Highway 333 (Iowa 333) at a diamond interchange. From Hamburg, I-29 continues to the northwest for seven miles (11 km) where it meets Iowa 2 three miles (4.8 km) east of Nebraska City, Nebraska. North of the Iowa 2 interchange, the Interstate straightens out to the north; interchanges serving Percival, Thurman, and Bartlett are spaced out every 4.5 miles (7.2 km). At the US 34 interchange near Glenwood, I-29 is joined by US 275.[1]

I-29 is flanked by the Loess Hills

North of Glenwood, I-29/US 275 continue north toward Council Bluffs. Near Lake Manawa, US 275 splits away from I-29 at the Iowa 92 interchange. The Interstate meets I-80 0.75 miles (1.21 km) north of the split. The two Interstates head west together through southern Council Bluffs for three miles (4.8 km) on separate carriageways. Just before I-80 crosses the Missouri River into Nebraska, I-29 immediately turns to the north. Two miles (3.2 km) to the north is a modified Y interchange with US 6 and the eastern end of I-480.[1]

North of Council Bluffs, I-29 passes the eastern terminus of I-680 near Crescent. I-29 travels north for nine miles (14 km) before intersecting with the western terminus of I-880 near Loveland. I-29 continues north for four miles (6.4 km) to Missouri Valley, where it intersects US 30. North of Missouri Valley, the Interstate turns to the northwest toward Modale and then straightens out again south of Mondamin, where I-29 meets the western end of Iowa 127. From Mondamin, it travels north for 23 miles (37 km) to the Iowa 175 interchange at Onawa, passing Little Sioux and Blencoe.[1][3]

I-29 closely parallels the Missouri River in Sioux City.

North of Onawa, I-29 continues northwest for 15 miles (24 km) toward Sloan, where it meets the western end of Iowa 141. As it approaches the Sioux City metro area, it passes the Sioux Gateway Airport at Sergeant Bluff. At the Singing Hills Boulevard interchange, northbound is joined by southbound U.S. Highway 75 Business (US 75 Bus.). One mile (1.6 km) later, US 75 Bus. ends at the cloverleaf interchange with US 20/US 75, which is also the eastern end of I-129.[1]

For the next three miles (4.8 km) north of the I-129 interchange, I-29 runs closely, as close as 200 feet (61 m), to the Missouri River. The Interstate follows the curve of the river and turns to the west. It meets Gordon Drive, which carries US 20 Bus. US 20 Bus. traffic is directed onto the Interstate for 0.5 miles (0.80 km) before it exits via a volleyball interchange, which represents the national northern end of US 77.[1] I-29 continues west along the Missouri River, and, after the Big Sioux River converges into the Missouri, I-29 follows the Big Sioux. Shortly before it crosses the Big Sioux into South Dakota, Iowa 12 splits away to the north.[4]


Interchange with I-680 looking toward the Mormon Bridge in Council Bluffs on June 16, 2011, during the 2011 Missouri River floods

Construction of I-29 began in the late 1950s in the Sioux City area. The first section to open, a three-mile-long (4.8 km) stretch from the Big Sioux River to the then–US 20/US 77 bridge across the Missouri River opened around October 1, 1958. In September 1961, I-29 was extended across the Big Sioux River to South Dakota. On April 1, 1962, some of the northbound directional spans collapsed into the Big Sioux River at the South Dakota state line as a result of flooding and bridge scour.[5][6][7]

North of Council Bluffs, a 20-mile (32 km) section to Missouri Valley opened in November 1958. By December 1967, the two sections were connected, creating 100 miles (160 km) of continuous interstate highway.[2] Due to a shortage of male workers, at least 20 women were enlisted to help build this section of I-29. The women were paid $2.00 hourly (equivalent to $17.55 hourly in 2022[8]), the same wage as men would have earned.[9]

Construction of I-29 in the Council Bluffs area was completed in 1970, and the route was open to Glenwood in the same year. Additional interchanges were added in the Sioux City and Council Bluffs areas between 1970 and 1971. The last 30 miles (48 km) of Interstate were constructed and opened in sections over the next two years; the last section opened on December 15, 1972.[2]

In 1973, US 34 was expanded to four lanes near Glenwood, which resulted in US 34 being rerouted onto I-29 for three miles (4.8 km).[2] In 2003, US 275 was rerouted onto I-29 from the same interchange near Glenwood northward to Iowa 92 at Council Bluffs. The former US 275 alignment was turned over to Mills and Pottawattamie counties.[10]

Much of I-29 was built next to existing highways, most notably US 75. When the section of I-29 opened between Council Bluffs and Missouri Valley, US 75 was rerouted onto I-29.[11] When construction connecting the Sioux City and Council Bluffs segments was completed, US 75 was again rerouted onto I-29.[12] In the mid-1980s, US 75, from Council Bluffs to Sioux City, was completely rerouted out of Iowa, instead extending up the former US 73 corridor in Nebraska.[13]

Exit list

FremontWashington Township0.0000.000
I-29 south – St. Joseph, Kansas City
Continuation into Missouri
Iowa 333 east – Hamburg
Benton Township10.14416.32510 Iowa 2 – Sidney, Nebraska City
15.45824.87715 CR J26 – Percival
Scott Township19.91732.05320 CR J24 – McPaul, ThurmanFormerly Iowa 145
24.44739.34424 CR L31 (To CR J10) – Bartlett, Tabor
MillsPlattville Township32.38652.12032Pacific Junction, PlattsmouthFormerly US 34
US 34 / US 275 south – Glenwood, Red Oak
Southern end of US 275 overlap
St. Marys Township43.80570.49742 CR H10 – BellevueFormerly Iowa 370
PottawattamieCouncil Bluffs47.86577.03147
US 275 north / Iowa 92 – Lake Manawa
Northern end of US 275 overlap
I-80 / US 6 east – Des Moines
Signed as exit 48 southbound; I-80 west exits 4A-B

I-80 Express / US 6 west – Omaha
Northbound exit and southbound entrance; I-80 east exit 4
49.23079.22849South Expressway – DowntownFormer Iowa 192 north; formerly signed as exit 3 on old alignment
50.68381.56650S. 24th Street – Mid-America CenterFormerly signed as exit 1B on old alignment
I-80 west – Omaha
I-80 east exits 1A-B

I-80 Express / US 6 east – Des Moines
Southern end of US 6 overlap; southbound exit and northbound entrance; I-80 west exit 1
52.37884.29452Nebraska Avenue – Riverboat Casino, Dog Track-Casino
53.19985.61553A9th Avenue / Harrah's Boulevard – Casino
I-480 / US 6 west – Omaha, Eppley Airfield
Clockwise terminus of I-480; northern end of US 6 overlap; northbound left exit
54.20487.23354AAvenue GSouthbound exit and entrance only
54.62387.90754BN. 35th StreetNorthbound exit and entrance only; closed May 2021
55.71589.66555N. 25th Street
56.91791.59956N. 16th Street – Council Bluffs, Business DistrictSouthbound left exit and northbound entrance only; formerly Iowa 192
Crescent Township61.96699.72561

I-680 west / CR G37 east – Crescent, North Omaha
Clockwise terminus of I-680; signed as exits 61A (east) and 61B (west)
township line
66.465106.96566Honey Creek
Rockford Township71.623115.26671
I-880 east / Loess Hills National Scenic Byway (Hitchcock Loop) – Des Moines
Western terminus of I-880; former I-680 east, originally I-80N
71.988115.85372Loveland / Loess Hills National Scenic Byway (Hitchcock Loop)Pottawattamie CR G12 (west) and CR G14 (east)
HarrisonMissouri Valley75.786121.96675 US 30 – Missouri Valley, Blair Nebraska
Taylor Township82.088132.10882 CR F50 – Modale
Morgan Township89.309143.72989
Iowa 127 east – Mondamin
Little Sioux Township95.714154.03795 CR F20 – Little Sioux
MononaSherman Township105.347169.540105 CR K45 – Blencoe
Onawa112.326180.771112 Iowa 175 – Onawa, Decatur
township line
120.210193.459120 CR E24 – Whiting
WoodburySloan Township127.571205.306127
Iowa 141 east – Sloan
Salix133.970215.604134Salix (CR K25)
135.708218.401135Port Neal Landing (CR D51)
Sergeant Bluff141.194227.230141 CR D38 / Loess Hills National Scenic Byway – Sergeant Bluff, Sioux Gateway Airport
Sioux City143.413230.801143

US 75 Bus. north (Singing Hills Boulevard) – Bridgeport, Industrial Park
Southern end of US 75 Business overlap; US 75 Business southbound traffic follows I-29 northbound

I-129 west / US 75 Bus. ends / US 20 / US 75 – Le Mars, Fort Dodge, South Sioux City
Northern end of US 75 Business overlap; signed as exits 144A (east/north) and 144B (west/south); I-129 exits 1A-B
147.476237.340147Floyd Boulevard, Virginia StreetSigned as exit 147A northbound
148.050238.263147BGordon Drive (US 20 Bus.) / Nebraska Street – Downtown, Tyson Events CenterNorthbound exit and southbound entrance only

US 77 south / US 20 Bus. west / Wesley Parkway north – South Sioux City
Southern end of US 20 Business overlap; southbound access via exit 149

To US 77 south (US 20 Bus. west) / Hamilton Boulevard – Riverfront
Wesley Parkway north – South Sioux City
Northbound signed as Hamilton Boulevard only
Iowa 12 north (Riverside Boulevard) / Loess Hills National Scenic Byway – Akron
Northern end of Iowa 12 overlap; IowaDOT signs this as southern end of Iowa 12
Big Sioux River151.826244.340Iowa–South Dakota state line

I-29 north – Sioux Falls
Continuation into South Dakota
1.000 mi = 1.609 km; 1.000 km = 0.621 mi


  1. ^ a b c d e f g 2009 Volume of Traffic on the Primary Road System of Iowa (PDF) (Report). Iowa Department of Transportation. January 1, 2009. Retrieved September 8, 2010.
  2. ^ a b c d Completion Map of Interstate System (PDF) (Map). Iowa Department of Transportation. January 1, 1982. Archived from the original (PDF) on September 29, 2011. Retrieved September 8, 2010.
  3. ^ Special Committee on U.S. Route Numbering (October 6, 2019). "2019 Annual Meeting Report to the Council on Highways and Streets" (PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. Archived from the original (PDF) on October 23, 2019. Retrieved October 9, 2019. "Ballot" (PDF). Archived from the original (PDF) on October 23, 2019.
  4. ^ Sioux City, Iowa (PDF) (Map). Iowa Department of Transportation. 2010. Retrieved September 8, 2010.
  5. ^ "Rain, storms follow weekend of storms; stir fears of floods". Lodi News-Sentinel. United Press International. April 2, 1962. p. 5. Retrieved January 29, 2015.
  6. ^ "I-29 bridge collapse". Sioux City Journal. April 22, 2012. Retrieved January 29, 2015.
  7. ^ Richardson, E. V.; Lagasse, P. F. (1999). Stream Stability and Scour at Highway Bridges. American Society of Civil Engineers. p. 57. ISBN 9780784474655.
  8. ^ 1634–1699: McCusker, J. J. (1997). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda (PDF). American Antiquarian Society. 1700–1799: McCusker, J. J. (1992). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States (PDF). American Antiquarian Society. 1800–present: Federal Reserve Bank of Minneapolis. "Consumer Price Index (estimate) 1800–". Retrieved May 28, 2023.
  9. ^ "Can't get men, paving contractor is hiring women". Toledo Blade. Associated Press. October 13, 1967. p. 5. Retrieved September 8, 2010.
  10. ^ Iowa State Highway Map (PDF) (Map). Iowa Department of Transportation. 2004. § B2. Retrieved September 8, 2010.
  11. ^ Iowa State Highway Map (PDF) (Map). Iowa State Highway Commission. 1959. § L2:M3. Retrieved September 8, 2010.
  12. ^ Iowa State Highway Map (PDF) (Map). Iowa State Highway Commission. 1969. § G1:L3. Retrieved September 8, 2010.
  13. ^ Iowa State Highway Map (Map). Iowa Department of Transportation. 1985. § A5:B3.
  14. ^ Transportation Map (PDF) (Map). Iowa Department of Transportation. 2010. Retrieved 2010-09-08.

External links

Interstate 29
Previous state:
Iowa Next state:
South Dakota