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 10 is a state highway that runs 104+1⁄2 miles (168.2 km) across the state of Iowa. It begins where South Dakota Highway 46 crosses the Big Sioux River into Iowa north of Hawarden. It ends east of Havelock at an intersection with Iowa Highway 4.