Interstate 80 (I-80) is a transcontinental Interstate Highway in the United States, stretching from San Francisco, California, to Teaneck, New Jersey. In Iowa, the highway travels west to east through the center of the state. It enters the state at the Missouri River in Council Bluffs and heads east through the southern Iowa drift plain. In the Des Moines metropolitan area, I-80 meets up with I-35 and the two routes bypass Des Moines together. On the northern side of Des Moines, the Interstates split and I-80 continues east. In eastern Iowa, it provides access to the University of Iowa in Iowa City. Northwest of the Quad Cities in Walcott is Iowa 80, the world's largest truck stop. I-80 passes along the northern edge of Davenport and Bettendorf and leaves Iowa via the Fred Schwengel Memorial Bridge over the Mississippi River into Illinois.

Before I-80 was planned, the route between Council Bluffs and Davenport, which passed through Des Moines, was vital to the state. Two competing auto trails, the Great White Way and the River-to-River Road, sought to be the best path to connect three of the state's major population centers. The two trails combined in the 1920s and eventually became US Highway 32 (US 32) in 1926. US 6, which had taken the place of US 32, became the busiest highway in the state. In the early 1950s, plans were drawn up for the construction of an Iowa Turnpike, to be the first modern four-lane highway in the state, along the US 6 corridor. Plans for the turnpike were shelved when the Interstate Highway System was created in 1956.

Construction of I-80 took place for over 14 years. The first section of the Interstate opened on September 21, 1958, in the western suburbs of Des Moines. New sections of the highway opened up regularly over the next 12 years, even though construction in eastern Iowa was completed in 1966. The final piece of I-80 in Iowa, the Missouri River bridge to Omaha, Nebraska, opened on December 15, 1972. By the 1980s, I-80 had fallen into disrepair in Iowa and across the country. Federal funding was freed up in 1985 to allow reconstruction of the highway.

Route description I-80 is the longest Interstate Highway in Iowa. It extends from west to east across the central portion of the state through the population centers of the Omaha–Council Bluffs metropolitan area, Des Moines metropolitan area, and Quad Cities. The majority of the highway runs through farmland, yet roughly a third of Iowa's population live along the I-80 corridor. The route closely follows the Iowa Interstate Railroad, which was once the Chicago, Rock Island and Pacific Railroad Main Line in Iowa.

Western Iowa I-80 enters Iowa on a bridge over the Missouri River, where it leaves Omaha, Nebraska, to enter Council Bluffs. Almost immediately after landing on the Iowa side of the bridge, it meets I-29 and US 6 at a Y interchange. At the interchange, I-80 splits into a local–express lane configuration. The inner express lanes do not provide any connection to I-29 nor to any of the intermediate interchanges between the two junctions with I-29. The outer local lanes are concurrent with I-29 through southern Council Bluffs for . The speed limit through this section is . The South 24th Street interchange serves a commercial area anchored by the Mid-America Center and Horseshoe Casino. The South Expressway exit, which previously marked the southern end of Iowa Highway 192 (Iowa 192), is adjacent to a big-box store commercial center. At the East System interchange in Council Bluffs; I-29 heads south while I-80 and US 6 head to the northeast.

East of the I-29 split, I-80 travels northeast for the next . It passes through eastern Council Bluffs where it serves a commercial/residential area. At exit 8, US 6 exits the freeway and heads west. The Interstate leaves Council Bluffs and speed limit increases to . Here, I-80 roughly follows the course of Mosquito Creek past Underwood and Neola, both of which are served by interchanges. About of Neola, I-80 curves to the east as it meets the eastern end of I-880 at a directional T interchange.

For the next , I-80 runs in more or less a straight line. Interchanges occur at regular intervals; of Pottwattamie and Cass county farmland separate each exit from the next. Near Avoca, it crosses the West Nishnabotna River and meets US 59. East of the interchange, the Interstate crosses the eastern branch of the West Nishnabotna River. As I-80 approaches the area north of Atlantic, there are three interchanges, Iowa 173, County Road N16 (CR N16), and US 71, which serve the western, central, and eastern parts of the city, respectively. Iowa 173, which serves Atlantic by way of Iowa 83, also connects to Elk Horn and Kimballton. US 71, which continues north toward Carroll, carries US 6 traffic to the Interstate. At this point, US 6 begins the first of three instances when its traffic is routed along I-80. In the eastern part of Cass County, the two routes meet the northern end of Iowa 148.

As I-80 and US 6 approach Adair, the highways curve slightly to the south to bypass the community. There are two interchanges in Adair; both of the intersecting roads, at one time or another, carried US 6. CR G30, the White Pole Road, was the original alignment of US 6, while CR N54 has not carried US 6 since 1980. Further east is an interchange with Iowa 25. About south of the interchange is Freedom Rock. Each year for Memorial Day, the rock is repainted with a patriotic scene by local artist Ray "Bubba" Sorenson II. Near Dexter, I-80 and US 6 graze the northwestern corner of Madison County. After , the routes enter Dallas County and meet CR F60, another former alignment of US 6.

Central Iowa Continuing east, the two routes follow a due-east section of highway, where they pass Earlham. Near the CR F90/CR P58 interchange, they start heading northeast towards Des Moines. At De Soto, US 6 splits away from I-80 at the interchange with US 169. Tourists who want to see the covered bridges of Madison County (made famous by the book The Bridges of Madison County) and the birthplace of John Wayne, are directed to follow US 169 south to Winterset. Between De Soto and Van Meter, the Interstate crosses the middle and north branches of the Raccoon River, which converge just south of the crossing of the North Raccoon River.

As the highway gets closer to Des Moines, it moves more sharply to the northeast. In southern Waukee, there is an interchange with Grand Prairie Parkway, the first diverging diamond interchange in the state. As I-80 enters West Des Moines, the speed limit lowers to and the path of the Interstate straightens out to the east at the Jordan Creek Parkway exit. The highway adds a third lane eastbound and drops the third lane westbound. Almost to the east is the interchange with I-35, which also marks the beginning of I-235. Eastbound I-80 exits the freeway via a flyover ramp to northbound I-35; eastbound I-235 begins as the continuation of the I-80 freeway. Locally, this exit is called the West Mixmaster.

I-80 shares the next with I-35 on a six-lane freeway where each direction's three lanes are separated by a Jersey barrier. They begin their journey together by heading north; they briefly run through West Des Moines and then cross into Clive at University Avenue. At the Clive–Urbandale city limits is the interchange with Hickman Road, which carries US 6. Hickman Road serves a truck stop to the west and the Living History Farms visitor center to the east. The two Interstates continue north through Urbandale where they pass Douglas Avenue. The Iowa 141 exit is at Rider Corner, the point where the I-35/I-80 freeway curves 90 degrees to the east.

East of the 86th Street exit, the freeway begins a slow descent toward the Des Moines River. Merle Hay Road, named for the first Iowan to die in World War I, carries Iowa 28 from the south to its northern end at the Interstates. They cross the Des Moines River just south of the mouth of Beaver Creek. to the east is Iowa 415 and further east is US 69. Between the interchanges there is a fourth lane in each direction. At the end of their together, I-35 exits to the north and I-235's eastern end is to the south at the East Mixmaster.

East of I-35, I-80 meets up with US 65 on the outskirts of Altoona. The two routes only share the highway for as US 65 splits away at the next exit. Here, US 6 rejoins I-80 for the second time and the Interstate returns to its four-lane configuration. After a third exit for Altoona, the Interstate resumes its rural limit. Near Colfax, the highways cross the South Skunk River. After an interchange with Iowa 117, the highway is forced to the north to avoid crossing the river multiple times. As it returns south to its original line, it meets CR F48, which was another former alignment of US 6. At the Iowa 14 exit in Newton, US 6 exits off the Interstate. East of Newton is an interchange that serves the Iowa Speedway.

east of the speedway is an exit for Iowa 224 which connects to Kellogg. After this interchange, the highway curves to the northeast and descends a hill to cross the North Skunk River. Shortly after the river, it curves back to the east and climbs up the hill. As the road straightens out, it begins a stretch of straight highway. Between the river and the Iowa 146 exit south of Grinnell, the farmland that surrounds the Interstate undulates. Past Grinnell, it passes through the footprint of the North English wind farm, with rows of turbines running parallel to the route. Just south of Malcom, it meets US 63. Further east, at exit 201 for Iowa 21, there are competing truck stops on either side of the freeway.

Eastern Iowa

Now in Iowa County, I-80 continues toward the eastern end of the stretch of straight highway. It turns slightly to the southeast near the Ladora exit and straightens again at the Marengo interchange, where Kinze Manufacturing, a farm implement manufacturer, advertises its business to passing travelers by arranging farm implements into sculptures. A few miles east, in Williamsburg, is the northern end of Iowa 149. The Williamsburg exit is the location of a Tanger Outlet Mall. The next interchange marks the southern end of US 151. Both the Iowa 149 and US 151 interchanges serve the Amana Colonies which are located to the north.

As I-80 enters the Iowa City area, the speed limit drops to . On the edge of Coralville is an interchange with US 218 and Iowa 27. This interchange is also the beginning of I-380, which heads north along US 218 and Iowa 27 toward Cedar Rapids and Waterloo. The I-80/I-380 interchange was identified as the most likely location in Iowa for a semi-trailer truck to overturn. According to the American Transportation Research Institute, 30 trucks rolled over at the interchange during the eight-year study period. The Iowa Department of Transportation (Iowa DOT) replaced the cloverleaf interchange with a turbine interchange, which opened to traffic in August 2023

At the I-380 interchange, I-80 becomes a six-lane freeway. The Coral Ridge Avenue exit provides access to US 6, which passes beneath the Interstate just before the interchange, and the eponymous shopping center located to the southeast. The 1st Avenue exit in Coralville, which was converted to a diverging diamond interchange in 2025 and Dubuque Street exit in Iowa City direct University of Iowa traffic to different parts of the university campus. The Iowa River flows between the two interchanges and also marks the boundary between Coralville and Iowa City. On Iowa City's east side are the Iowa 1 and Herbert Hoover Highway exits. Between them, the highway drops back to four lanes and the speed limit increases to .