# Interstate 29 in Iowa

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, I-29 runs on the flat land between the Missouri River and the Loess Hills, and is also part of the Lewis and Clark Trail.
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.
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.
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.
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.
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) to Exit 149, which represents the national northern end of US 77. 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.

## History

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.
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. 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 $18.86 hourly in 2024), the same wage as men would have earned.
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.
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). 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.
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. When construction connecting the Sioux City and Council Bluffs segments was completed, US 75 was again rerouted onto I-29. 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.
In March 2021, the Iowa DOT began a project to improve the I-29/I-480/West Broadway System Interchange at I-480's eastern terminus. The project was done to improve traffic flow, safety, and the functional design at that interchange as well as at the adjacent I-29 interchanges at 41st Street, 35th Street, Avenue G and 9th Avenue. The project is projected to be completed by the end of 2024.

## Exit list

| County | Location | mi | km | Exit | Destinations | Notes |
| Fremont | Washington Township | 0.000 | 0.000 | | I-29 south – St. Joseph, Kansas City | Continuation into Missouri |
| Fremont | Washington Township | 1.811 | 2.915 | 1 | Iowa 333 east – Hamburg | |
| Fremont | Benton Township | 10.144 | 16.325 | 10 | Iowa 2 – Sidney, Nebraska City | |
| Fremont | Benton Township | 15.458 | 24.877 | 15 | CR J26 – Percival | |
| Fremont | Scott Township | 19.917 | 32.053 | 20 | CR J24 – McPaul, Thurman | Formerly Iowa 145 |
| Fremont | Scott Township | 24.447 | 39.344 | 24 | CR L31 (To CR J10) – Bartlett, Tabor | |
| Mills | Plattville Township | 32.386 | 52.120 | 32 | CR L35 – Pacific Junction, Plattsmouth | Formerly US 34 |
| Mills | Plattville Township | 35.477 | 57.095 | 35 | US 34 / US 275 south – Glenwood, Red Oak | Southern end of US 275 overlap |
| Mills | St. Marys Township | 43.805 | 70.497 | 42 | CR H10 – Bellevue | Formerly Iowa 370 |
| Pottawattamie | Council Bluffs | 47.865 | 77.031 | 47 | US 275 north / Iowa 92 – Lake Manawa | Northern end of US 275 overlap |
| Pottawattamie | Council Bluffs | 48.526 | 78.095 | 48A | I-80 / US 6 east – Des Moines | Signed as exit 48 southbound; I-80 west exits 4A-B |
| Pottawattamie | Council Bluffs | 48.526 | 78.095 | 48B | I-80 Express / US 6 west – Omaha | Northbound exit and southbound entrance; I-80 east exit 4 |
| Pottawattamie | Council Bluffs | 49.230 | 79.228 | 49 | South Expressway – Downtown | Former Iowa 192 north; formerly signed as exit 3 on old alignment |
| Pottawattamie | Council Bluffs | 50.683 | 81.566 | 50 | S. 24th Street – Mid-America Center | Formerly signed as exit 1B on old alignment |
| Pottawattamie | Council Bluffs | 51.644 | 83.113 | 51 | I-80 west – Omaha | I-80 east exits 1A-B |
| Pottawattamie | Council Bluffs | 51.644 | 83.113 | 51 | I-80 Express / US 6 east – Des Moines | Southern end of US 6 overlap; southbound exit and northbound entrance; I-80 west exit 1 |
| Pottawattamie | Council Bluffs | 52.378 | 84.294 | 52 | Nebraska Avenue – Mid-America Center | |
| Pottawattamie | Council Bluffs | 53.199 | 85.615 | 53A | 9th Avenue / Harrah's BoulevardW. Broadway | Northbound exit and southbound entrance |
| Pottawattamie | Council Bluffs | 53.777 | 86.546 | 53B | I-480 / US 6 west – Omaha, Eppley Airfield | Clockwise terminus of I-480; northern end of US 6 overlap; signed as exit 53 southbound |
| Pottawattamie | Council Bluffs | 54.204 | 87.233 | 54 | W. Broadway9th Avenue / Harrah's Boulevard | Southbound exit and northbound entrance |
| Pottawattamie | Council Bluffs | 55.715 | 89.665 | 55 | N. 25th Street | |
| Pottawattamie | Council Bluffs | 56.917 | 91.599 | 56 | N. 16th Street – Council Bluffs, Business District | Southbound left exit and northbound entrance only; formerly Iowa 192 |
| Pottawattamie | Crescent Township | 61.966 | 99.725 | 61 | I-680 west / CR G37 east – Crescent, North Omaha | Clockwise terminus of I-680; signed as exits 61A (east) and 61B (west) |
| Pottawattamie | Crescent–Rockford township line | 66.465 | 106.965 | 66 | Honey Creek (CR L19) | |
| Pottawattamie | Rockford Township | 71.623 | 115.266 | 71 | I-880 east – Des Moines | Western terminus of I-880; former I-680 east, originally I-80N |
| Pottawattamie | Rockford Township | 71.988 | 115.853 | 72 | CR G12 – Loveland, Wilson Island State Park | |
| Harrison | Missouri Valley | 75.786 | 121.966 | 75 | US 30 – Missouri Valley, Blair Nebraska | |
| Harrison | Taylor Township | 82.088 | 132.108 | 82 | CR F50 – Modale | |
| Harrison | Morgan Township | 89.309 | 143.729 | 89 | Iowa 127 east – Mondamin | |
| Harrison | Little Sioux Township | 95.714 | 154.037 | 95 | CR F20 – Little Sioux | |
| Monona | Sherman Township | 105.347 | 169.540 | 105 | CR K45 – Blencoe | |
| Monona | Onawa | 112.326 | 180.771 | 112 | Iowa 175 – Onawa, Decatur | |
| Monona | Lincoln–Lake township line | 120.210 | 193.459 | 120 | CR E24 – Whiting | |
| Woodbury | Sloan Township | 127.571 | 205.306 | 127 | Iowa 141 east – Sloan | |
| Woodbury | Salix | 133.970 | 215.604 | 134 | Salix (CR K25) | |
| Woodbury | Salix | 135.708 | 218.401 | 135 | Port Neal Landing (CR D51) | |
| Woodbury | Sergeant Bluff | 141.194 | 227.230 | 141 | Loess Hills National Scenic Byway south (CR D38) – Sergeant Bluff, Sioux Gateway Airport | Southern end of Loess Hills NSB overlap; access to airport via Aviation Boulevard (formerly Iowa 378) |
| Woodbury | Sioux City | 143.413 | 230.801 | 143 | 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 |
| Woodbury | Sioux City | 144.473 | 232.507 | 144 | 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 |
| Woodbury | Sioux City | 147.476 | 237.340 | 147 | Floyd Boulevard / Virginia Street (US 20 Bus. east / Iowa 12 south) | Northern end of US 20 Business/Iowa 12 overlap; signed as exit 147A northbound |
| Woodbury | Sioux City | 148.050 | 238.263 | 147B | Gordon Drive (US 20 Bus. / Iowa 12) / Nebraska Street | Northbound exit and southbound entrance only; serves MercyOne Siouxland Medical Center |
| Woodbury | Sioux City | 148.493 | 238.976 | 148 | US 77 south / US 20 Bus. west (Wesley Parkway) – South Sioux City | Southern end of US 20 Business overlap; southbound access via exit 149 |
| Woodbury | Sioux City | 149.081 | 239.923 | 149 | To US 77 south / US 20 Bus. west (Wesley Parkway) / Hamilton Boulevard – Riverfront, South Sioux City | Northbound signed as "Hamilton Boulevard – Riverfront" only |
| Woodbury | Sioux City | 151.365 | 243.598 | 151 | Iowa 12 north (Riverside Boulevard) / Loess Hills National Scenic Byway – Akron | Northern end of Iowa 12/Loess Hills NSB overlap; IowaDOT signs this as southern end of Iowa 12 |
| Big Sioux River | Big Sioux River | 151.826 | 244.340 | Iowa–South Dakota line | Iowa–South Dakota line | Iowa–South Dakota line |
| Big Sioux River | Big Sioux River | 151.826 | 244.340 | | I-29 north – Sioux Falls | Continuation into South Dakota |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus Incomplete access |||||||