U.S. Highway 218 is an original United States Highway, created in 1926. Although technically a spur of U.S. Route 18, US 218 neither begins nor ends at US 18, but overlaps US 18 for 8 miles (13 km) near Charles City, Iowa. US 218 begins at U.S. Route 136 in downtown Keokuk and ends 319 miles (513 km) away at Interstate 35 and U.S. Route 14 at Owatonna, Minnesota. A large portion of US 218 in Iowa is part of the Avenue of the Saints, which connects St. Louis, Missouri, and Saint Paul, Minnesota.
Iowa Highway 3 (Iowa 3) is a state highway that runs from east to west across the state of Iowa. It is the longest state highway in Iowa, at 323 miles (520 km) long. Iowa 3 begins at the South Dakota state line where it continues as South Dakota Highway 50 and ends at the Northwest Arterial at the Dubuque city limits. It is designated the American Veterans Memorial Highway for its entirety. It is located approximately halfway between Interstate 80 and Interstate 90.
Iowa Highway 8 is a state highway that runs from east to west in east central Iowa. Highway 8 is a short state highway in Iowa, at only 14 miles (23 km) long. Iowa 8 begins at an intersection with U.S. Highway 63 in Traer and ends at an intersection with U.S. Highway 218 northwest of Garrison. The route has largely remained the same since its designation.
Iowa Highway 15 is a north–south state highway in northern Iowa. It is 63+1⁄2 miles (102.2 km) long. The southern end of Iowa 15 is 7 miles (11 km) east of Pocahontas at an intersection with Iowa Highway 3. The northern end is at the Minnesota border, where the highway continues north as Minnesota State Highway 15 near Fairmont, Minnesota. Prior to 1969, the route was known as Iowa Highway 44; it was renumbered to match the highway in Minnesota.
Iowa Highway 38 is a 98-mile-long (158 km) state highway that runs through eastern Iowa. Iowa 38 begins at Iowa Highway 92 in Muscatine and ends at Iowa Highway 3 near Greeley.
Iowa Highway 93 is a state highway that runs from east to west through two counties in northeastern Iowa. Iowa 93 is 29.55 miles (47.56 km) long. The eastern terminus of Iowa 93 is at its junction with Iowa Highway 150 in Fayette. The western terminus of Iowa 93 is at an intersection with U.S. Route 63 4 miles (6.4 km) west of Tripoli.
U.S. Highway 30 (US 30) is a major east–west U.S. Highway which spans 330 miles (530 km) across the state of Iowa. It is the longest primary highway in the state and is maintained by the Iowa Department of Transportation. The route in Iowa begins at the Missouri River crossing at Blair, Nebraska, and ends at the Mississippi River crossing at Clinton, Iowa. Along the way, it serves Denison and Carroll in western Iowa, Boone, Ames, and Marshalltown in central Iowa, and Tama, Cedar Rapids, and DeWitt in eastern Iowa. Cutting across the central portion of the state, US 30 runs within close proximity of the Union Pacific Railroad's Overland Route for its entire length.
Iowa Highway 48 is a 48-mile-long (77 km) state highway which runs from north to south in southwest Iowa. It begins at the northern edge of Shenandoah at U.S. Highway 59 and ends at U.S. Highway 6 near Lewis. The highway has seen few changes since its creation.
Iowa Highway 85 (Iowa 85) is a short state highway in east-central Iowa. The route begins at the eastern city limit of Montezuma and ends at Iowa 21 east of Deep River. Created in 1920 as a spur route connecting What Cheer to Primary Road No. 2, it is an original route in the Iowa primary highway system. In the early 1930s, the route was extended north to Deep River and west to Montezuma. By the end of the decade, Iowa 21 had taken over the north–south portion of the route. Except for both endpoints shifting slightly, Iowa 85 has largely stayed the same since the 1930s.
Iowa Highway 78 is a 59-mile-long (95 km) state highway which runs from east to west in southeastern Iowa. The route begins east of Martinsburg at Iowa Highway 149, and ends at U.S. Highway 61 east of Morning Sun. The route has existed since the 1920s, when it was a short spur route between Olds and Winfield. By the 1950s, the route reached its current extents.
Iowa Highway 58 is a state highway that runs from north to south in northeast Iowa. A five-and-a-half-mile (8.9 km) portion of the highway is overlapped by the Avenue of the Saints. Iowa 58 begins at U.S. Highway 63 (US 63) in Hudson and ends at an interchange with US 218 and Iowa 57. Iowa 58's route has changed many times in its history, but has always served Black Hawk County.
Iowa Highway 105 was an east–west route which ran 34 miles (55 km) from Lake Mills to St. Ansgar in northern Iowa. Since January 1, 1993, Iowa 105 has been known as County Road 105 (CR 105). County Road 105 was the first county road in Iowa to not follow the standard alphanumeric route numbering system.
Iowa Highway 150 (Iowa 150) is an 85-mile-long (137 km) state highway in eastern and northeastern Iowa. It begins at U.S. Route 218 (US 218) in Vinton and ends at US 52 and Iowa 24 in Calmar. From Vinton, it heads north and east towards Urbana where it meets Interstate 380 (I-380) and Iowa 27, the Avenue of the Saints highway. At Independence, it intersects US 20 on the south side of town. Further north, it converges with Iowa 3 in Oelwein.
Iowa Highway 182 (Iowa 182) is a 9-mile-long (14 km) state highway in the northwestern corner of Iowa. It begins at U.S. Highway 18 (US 18) in Inwood and ends at Iowa 9 southeast of Larchwood. The highway has been in the primary highway system since 1930, when it was known as Iowa 26. On January 1, 1969, Iowa 26 and Iowa 182 swapped designations.
Iowa Highway 281 is a 28-mile-long (45 km) state highway in north-central Iowa. Iowa 281 begins at the eastern city limits of Waterloo and ends at Iowa Highway 150 south of Oelwein.
Iowa Highway 346 is a short state highway in north-northeastern Iowa. Iowa 346 begins at U.S. Route 218 / Iowa Highway 27 at Nashua, Iowa and ends at the intersection of U.S. Highway 18 and U.S. Highway 63 south of New Hampton.
U.S. Highway 161 was a U.S. Highway in Iowa that ran from Keokuk to Dubuque by way of Cedar Rapids. It was designated in 1925 and signed in 1926 along two primary highways. The route began at the Missouri River with US 61 southwest of Keokuk ran north through Mount Pleasant and Iowa City to Cedar Rapids. There, it turned to the northeast through Anamosa and Monticello towards Dubuque. The route ended at US 61 in Key West, a few miles west of Dubuque.
U.S. Highway 18 (US 18) is the northernmost east–west U.S. Highway in the state of Iowa. As with all state highways in Iowa, it is maintained by the Iowa Department of Transportation (Iowa DOT). It enters the state by crossing the Big Sioux River between Inwood and Canton, South Dakota. It travels 311 miles (501 km) and connects Spencer, Mason City and Charles City. The highway leaves the state via the Marquette–Joliet Bridge over the Mississippi River at Marquette. Prior to becoming a U.S. Highway, the route US 18 follows was known as Primary Road No. 19 and the National Parks Pike.
Iowa Highway 412 (Iowa 412) was a state highway in Waterloo, Iowa. It began at U.S. Highway 63 (US 63) in southwestern Waterloo and traveled to the east and northeast approximately four and three-quarters miles (7.6 km) to US 218 in southeastern Waterloo. The route served as a southern bypass of Waterloo. The highway was added to the primary highway system in 1960 and given to the City of Waterloo in 1983. It was replaced in function by US 20, which that year relocated onto a freeway less than one-half mile (800 m) south of San Marnan Drive.
U.S. Highway 63 (US 63) is a United States Highway that runs through the eastern third of Iowa. It begins at the Missouri state line southwest of Bloomfield and travels north through Ottumwa, Oskaloosa, Tama, Waterloo, and New Hampton. It ends at the Minnesota state line at Chester. Between Ottumwa and Oskaloosa, the highway is a four-lane controlled-access highway. Through Waterloo and New Hampton, it is partially controlled; that is, the road as both grade-separated interchanges and at-grade intersections. The rest of the highway is largely a two-lane rural highway.
Iowa 3 near Clarksville 
US 63 near Tripoli 
