Interstate 129

Interstate 129 overlays 3.5 miles of U.S. 20 from just west of the Lake Avenue underpass outside South Sioux City, Nebraska to the directional cloverleaf interchange joining U.S. 20/75 with I-29 in Sioux City, Iowa. U.S. 20 extends west from I-129 along an expressway another 2.5 miles beyond Crystal Lake. U.S. 20/75 encircle the eastern side of Sioux City along a freeway bypass east to Gordon Drive (U.S. 20 Business) and north to Floyd Boulevard (U.S. 75 Business). I-129/U.S. 20-75 span the Missouri River across the Sergeant Floyd Memorial Bridge. The 2,607 foot long bridge was built in 1976.¹

East

U.S. 20 proceeds one mile east from Elgin Avenue to the cloverleaf interchange (Exit 1) with U.S. 75 south and U.S. 77 outside South Sioux City. 06/17/15

Milepost zero for Interstate 129 stands at the crossover preceding the Lake Avenue underpass just beyond this shield assembly along U.S. 20 eastbound. 06/17/15

U.S. 75 combines with U.S. 77 south from I-129/U.S. 20, 14 miles to Winnebago in Thurston County. 06/17/15

Exit 1A departs from I-129/U.S. 20 east for U.S. 75/77 south to the nearby Dakota/Thurston County Fairgrounds and Dakota City. 06/17/15

Exit 1B loops onto U.S. 77 north to South Sioux City and Downtown Sioux City, Iowa. U.S. 77 concludes in 3.4 miles at I-29 and U.S. 20 Business (Gordon Drive). 06/17/15

East North

U.S. 75 combines with I-129/U.S. 20 east into Sioux City, Iowa. 06/17/15

The previous first shield for Interstate 129 east. 04/20/07

Ascending across wetland areas linking Crystal Cove and Gateway Lake, I-129/U.S. 20-75 advance a quarter mile to Exit 2 for Dakota Avenue (U.S. 20 Business). 06/17/15

I-129/U.S. 20-75 cross over BNSF Railroad lines leading into the parclo interchange (Exit 2) with Dakota Avenue / IBP Avenue. 06/17/15

Dakota Avenue north through South Sioux City is U.S. 20 Business, though the route is sparsely signed. U.S. 20 Business combines with U.S. 77 across the Missouri River into Sioux City, where it turns onto Gordon Drive east back to U.S. 20. 06/17/15

Continuing east from Dakota Avenue, I-129/U.S. 20-75 meet Interstate 29 in two miles. Exit numbers along I-129 reset at the Iowa state line. 06/17/15

The freeway bends southward across agricultural areas between G Street and the Missouri River. 06/17/15

The directional cloverleaf interchange (Exit 1) with Interstate 29 lies at the east end of the Sergeant Floyd Memorial Bridge. 06/17/15

The succeeding ramp (Exit 1A) connects with I-29 south to Sioux Gateway Airport (SUX). 06/17/15

Climbing onto the Sergeant Floyd Memorial Bridge across the Missouri River. 06/17/15

Trailblazers for U.S. 75 Business preceded Exit 1A for I-29 south. Established in 2002, U.S. 75 Business in Sioux City follows a combination of I-29 south, Singing Hills Boulevard east and Old Highway 75 / Lewis Boulevard north. 04/20/07

Interstate 129 ends within the exchange joining U.S. 20/75 with I-29. I-29 heads south to Council Bluffs and Kansas City. 06/17/15

Interstate 29 runs along the Missouri Riverfront northward to Downtown Sioux City en route to Sioux Falls, South Dakota. Beyond Sioux City, U.S. 20 continues to Fort Dodge and Waterloo while U.S. 75 ventures north to Le Mars. 06/17/15

West South

Interstate 129 begins westbound along U.S. 20/75 within the exchange at I-29. The route however is not acknowledged until Nebraska. 04/20/07

I-129/U.S. 20-75 cross the Missouri River three miles south of Downtown Sioux City. 06/17/15

The Nebraska state line lies midway across the Sergeant Floyd Memorial Bridge. 06/17/15

A parclo interchange (Exit 2) joins Interstate 129 with Dakota Avenue in the city of South Sioux City in one mile. 06/17/15

The first of two confirming markers for I-129 west stands ahead of the C Avenue overpass. 06/17/15

Dakota Avenue leads north into South Sioux City as U.S. 20 Business. The bannered route is only signed at the south split with U.S. 77. 06/17/15

Exit 2 leaves I-129/U.S. 20-75 west for Dakota Avenue. Dakota Avenue is the historic alignment of U.S. 73/77 between Dakota City and South Sioux City. 06/17/15

U.S. 75 separates with I-129/U.S. 20 west at the forthcoming cloverleaf interchange (Exit 1) with U.S. 77. 06/17/15

I-129/U.S. 20-75 cross over BNSF Railroad lines and an area of wetlands south of Crystal Cove Park and ahead of U.S. 77 at Exits 1 B/A. 06/17/15

Exit 1B departs next from I-129/U.S. 20-75 west for U.S. 77 north into South Sioux City. 06/17/15

U.S. 77 north ends just across the Missouri River at I-29 and U.S. 20 Business (Gordon Drive). Historically it continued west along I-29 to Iowa 12 north. 06/17/15

U.S. 75 combines with U.S. 77, 16 miles south from I-129/U.S. 20 at Exit 1 A to Dakota City, Homer and a roundabout at Winnebago. 06/17/15

The west end shield for Interstate 129 stands beyond the Lake Avenue underpass along U.S. 20. 04/20/07

Milepost zero for I-129 follows this distance sign posted six miles from the village of Jackson and 18 miles southeast of the Dixon County seat of Ponca. 06/17/15

Photo Credits:

04/20/07, 06/17/15 by AARoads

Connect with:
Interstate 29
U.S. 20
U.S. 75

Page Updated 02-12-2020.