Iowa Highway 17 is a 103-mile-long (166 km) north–south state highway that traverses primarily rural areas in central and north-central Iowa. Iowa 17's southern end is near Granger in Dallas County at a freeway interchange with Iowa Highway 141, and its northern terminus is at an intersection with U.S. Highway 18 at the Kossuth-Hancock county line near Wesley.
Iowa Highway 4 is a state highway which runs from north to south across the state of Iowa. It is 146 miles (235 km) long, beginning at an intersection with Iowa Highway 44 in Panora and ending at the Minnesota state line north of Estherville. It continues north as Minnesota State Highway 4. The route was created on January 1, 1969, when several route designations were changed to match other states' route numbers. Before 1969, Iowa 4 was known as Iowa 17.
Iowa Highway 25 (Iowa 25) is a north–south highway in the southwest and west-central portion of the state. It begins at Iowa 2 seven miles (11 km) south of Clearfield. It heads north along a two-lane road through Creston, Greenfield, and Guthrie Center on its way to its northern end at U.S. Route 30 (US 30) near Scranton.
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 340 connected U.S. Highway 18 Business in McGregor to Pikes Peak State Park. It was designated in 1936 to connect Pikes Peak State Park to the primary highway system, which it did until it was turned over to Clayton County in 2003. It was turned over along with 700 miles (1,100 km) of other short highways that primarily served local traffic. It was mostly replaced by County Road X56. Aside from a short connector to the state park gate, the route was a part of the Great River Road.
The primary highway system makes up over 9,000 miles (14,000 km), approximately 8 percent of the U.S. state of Iowa's public road system. The Iowa Department of Transportation is responsible for the day-to-day maintenance of the primary highway system, which consists of Interstate Highways, United States Highways, and Iowa state highways. Currently, the longest primary highway is U.S. Highway 30 at 332 miles (534 km). The shortest highway is Interstate 129 at 0.27 miles (430 m).
U.S. Highway 77 (US 77) is the shortest U.S. Highway in the state of Iowa. It crosses into Iowa over the Missouri River from South Sioux City, Nebraska, at Sioux City and runs approximately three-tenths mile (500 m) to an interchange with Interstate 29 where the road continues north as Wesley Parkway. Like all other state highways in Iowa, the route is maintained by the Iowa Department of Transportation.
Iowa Highway 15 (Iowa 15) was a short state highway in Van Buren County. It ran from the Missouri state line, where it connected to Route 15 to Iowa 2 in Milton. The highway was designated on January 1, 1969, when the Iowa State Highway Commission renumbered several state highways in order to match up with adjoining highways in neighboring states. The route ceased to exist on July 1, 2003, when the Iowa Department of Transportation turned over 700 miles (1,100 km) of state highways that mostly served local traffic. While it was in service, there were two Iowa 15s in the state; the other was significantly longer and located in the northern part of the state thus avoiding confusion between the two routes.
Beginning in 1979 and lasting through the early 1980s, a series of agreements between the Iowa Department of Transportation and individual county boards of supervisors led to a mass transfer of jurisdiction of several state highways in Iowa. County boards of supervisors were asked to convene functional classification boards in order to review the classification all of the highway miles within each respective county. Control of roads that were classified as trunk roads or trunk collector roads were transferred to the counties, while roads classified as arteries or arterial collectors were transferred to the state department of transportation. The vast majority of transfers took place in 1980.
In late 1925, the Iowa State Highway Commission, now known as the Iowa Department of Transportation, announced plans to renumber several state highways. The changes to the highway system were a result of the creation of the United States Numbered Highway System. The new U.S. Highways replaced several of the state's primary roads and other routes were renumbered in order to eliminate driver confusion between the two systems. As the new highways were being signed, Iowa's state highways were given a new circular route marker. Previously, the primary road number was stenciled in black onto a telegraph pole over a band of yellow paint.
Iowa Highway 7 was a state highway that existed from 1957 to 1968. It began at the interchange between Interstate 29 (I-29), U.S. Highway 20, and U.S. Highway 77 in Sioux City and traveled north to end at Iowa 3 west of Le Mars. The route of Iowa 7 was an original primary road in 1920, but then it was known as Primary Road No. 29 and later Iowa 29. When I-29 was designated to come through Iowa in the 1950s, Iowa 29 was renumbered Iowa 7. Through Sioux City, the highway was well traveled, especially near I-29 and the downtown area; the inverse was true at the rural northern end. Subsequently, Iowa 7 was removed from the primary highway system in 1968.
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 4 
Iowa 5 
Iowa 7 
Iowa 15 
Iowa 17 
Iowa 23 
Iowa 26 
Iowa 39 
Iowa 44 
Iowa 60 
Iowa 70 
Iowa 76 
Iowa 81 
Iowa 114 
Iowa 130 
Iowa 182 
Iowa 202 
Iowa 254 
Iowa 322 
Iowa 985 
