Interstate 29 (I-29): Route, State Miles, Flood History and Crash Data

How long is I-29?

The January 2026 FHWA Route Log credits I-29 with 750.80 miles. Wikipedia's figure, 750.58 miles, is within a quarter mile of that. Interstate Guide gives 755.51 miles from Kansas City to the border at Pembina.

South Dakota holds the longest piece at 252.60 miles, followed by North Dakota at 217.49, Iowa at 151.93 and Missouri at 128.78. Iowa's number leaves out two stretches near Council Bluffs that the Route Log books to other routes: 3.00 miles listed as shared with I-80 and 9.91 miles with I-880. Interstate Guide counts them and puts Iowa at 164.66 miles, and the crash rates below use 164.84 miles for the state. Interstate Guide adds that the I-80 overlap was later split into a dual freeway. Missouri's row works the other way. I-29 shares 5.50 miles with I-35 in Kansas City, but its 128.78 Missouri miles are treated as already holding that stretch, so the Missouri rate uses them unchanged.

Where I-29 starts and ends

I-29 begins at the downtown freeway loop in Kansas City, Missouri, where it meets I-35, I-70, US 24, US 40 and US 71. It ends at the border crossing between Pembina, North Dakota, and Emerson, Manitoba, where Manitoba's Provincial Trunk Highway 75 carries traffic on toward Winnipeg.

Northbound, I-29 rides with I-35 over the Missouri River and then stays near that river past St. Joseph, Council Bluffs and Sioux City. It enters South Dakota over the Big Sioux River, passes Sioux Falls, Brookings and Watertown, and picks up US 81 northeast of Watertown; the two run together as far as Manvel, North Dakota. In North Dakota it parallels the Red River of the North through Fargo and Grand Forks before reaching the border.

Interstate junctions along I-29

Reading the list from Kansas City north, I-29 meets five main Interstates, one time each. I-70 and I-35 both come at the downtown Kansas City loop. The next one is I-80 at Council Bluffs, then I-90 on the northwest edge of Sioux Falls and I-94 in Fargo. Three-digit routes fill the gaps between them: I-435 and I-635 around Kansas City, I-229 at St. Joseph and again at Sioux Falls, I-480, I-680 and I-880 in and north of Council Bluffs, and I-129 at Sioux City.

Fatal crashes on I-29

From 2020 to 2024, crashes on the I-29 main line killed 91 people, roughly 18 a year. Over the whole route that equals 2.4 deaths per 100 route miles each year, about a quarter of the 9.5 average for the Interstate network. Of the 56 routes long enough to rank, I-29 is 54th, where 1 has the highest rate. The yearly count barely moved: 20 deaths in 2020, 18 in 2021, 20 in 2022, 16 in 2023 and 17 in 2024.

Missouri's rate is the highest on the route at 4.2, from 27 deaths over 128.78 miles, and Platte County, Missouri, had 13 deaths, the most of any county along I-29. South Dakota had more deaths in total, 29, but over 252.60 miles, so its rate is 2.3. Iowa comes in at 2.5 and North Dakota at 1.3, the lowest, with 14 deaths. After Platte, the counties with the most deaths are Union County, South Dakota, where the road enters the state from Iowa, with 8; Cass County, North Dakota, with 7; and Pottawattamie and Harrison counties in Iowa, with 6 and 5.

Counties with the most I-29 crash deaths

Bridges on I-29

The 2025 National Bridge Inventory lists 470 bridges carrying the I-29 main line, with a median construction year of 1972. Thirteen of them rate Poor, about 2.8 percent, while 313 rate Fair and 144 rate Good. Missouri has the most Poor bridges, 6 out of 105, followed by North Dakota with 4 and South Dakota with 3. None of Iowa's 123 bridges on the route rates Poor.

Some of the northbound spans over the Big Sioux River at the Iowa and South Dakota line collapsed on April 1, 1962, after flooding scoured their supports. At the other end of the route, I-29 and I-35 cross the Missouri River in Kansas City on the Christopher S. Bond Bridge, a cable-stayed span dedicated on September 27, 2010. The bridge was part of KcICON, a $245 million project that upgraded 4.7 miles of the road from I-70 north to Route 210 between March 2008 and February 2011.

Tolls on I-29

No toll facility on I-29 appears in FHWA's inventory as of January 1, 2023, so a trip from Kansas City to the Manitoba border costs nothing in tolls. The sources used for this page mention no toll or express lanes opened on the route since then. The Missouri River crossing in Kansas City once had a toll: the Paseo Bridge, the suspension bridge the Bond Bridge replaced, was dedicated in August 1954 as a toll facility.

I-29 auxiliary routes

I-29 has two three-digit routes, and one of them is used twice. In Missouri, the 14.94-mile I-229 leaves I-29 south of St. Joseph and rejoins it north of the city. South Dakota's I-229, at 11.39 miles, is a separate road that serves Sioux Falls and meets I-29 at exit 75. I-129 is the short spur from Sioux City toward South Sioux City, Nebraska, with 0.29 miles in Iowa and 3.21 in Nebraska.

How I-29 was built, and the floods that shut it

When the Interstate numbers were handed out on August 14, 1957, I-29 covered only Kansas City to Sioux Falls, and the road from Fargo to Canada was to be I-31. A Sioux Falls to Fargo link was added to the system in October 1957, and in a letter dated February 18, 1958, North Dakota's chief engineer proposed carrying I-29 over it and on to the border. The link was later built under the I-29 number.

Iowa opened its first segment on October 1, 1958, and its last, from the Missouri line to County Route J-64, on August 31, 1973. In South Dakota, the 84-mile section from Sioux City to Sioux Falls was dedicated on September 30, 1962. Missouri opened its final 18.7 miles, in Atchison County, on July 28, 1976, and South Dakota finished the stretch from exit 224 at Peever to exit 246 at New Effington in 1982.

From Kansas City to Sioux City the road follows the Missouri River, and high water there has closed it several times. The Great Flood of 1993 pushed traffic onto US 71 through Maryville and Clarinda, and the 2011 Missouri River flood closed I-29 for about two months. In March and April 2019 both directions closed for about 187 miles between St. Joseph and Council Bluffs, which Wikipedia describes as the largest Interstate closure by distance in the system's history. About 10 miles near Council Bluffs were still shut in May, and the full route was open again by October 2019. Our article on designing highways for flood resilience covers how agencies plan for this.

Recent rebuilding has centered on the cities. Iowa DOT began its Council Bluffs Interstate program in 2002, finished the West System Interchange in July 2017 and kept working on the East System Interchange through June 2020. The Sioux City I-29 project, begun in August 2010, wrapped up in 2019, and a new Brookings interchange at exit 130 opened on August 24, 2023.

I-29 traffic and road conditions

For closures, crash reports and winter road conditions on I-29 today, each of the four states runs its own traveler site. The links start in Missouri and end in North Dakota.

I-29 questions