Iowa's Six Neighbors: Mapping the Hawkeye State's Borders

Iowa sits at the heart of the American Midwest, bordered by six states—a combination of river boundaries and survey lines that reflect 19th-century territorial politics.

Border Details

• North — Minnesota: Survey line (43°30'N) established 1846-48. Prairie pothole region transitions to Minnesota's lake country.
• Northeast — Wisconsin: Mississippi River forms the entire border. Bluffs and coulees characterize the Driftless Area on both sides.
• East/Southeast — Illinois: Mississippi River continues as boundary. Quad Cities (Davenport/Bettendorf IA; Moline/Rock Island IL) straddle the river.
• South — Missouri: Des Moines River (upper) and survey line (lower). Historical "Honey War" (1839) border dispute over tax collection.
• West — Nebraska: Missouri River forms entire boundary. Omaha/Council Bluffs metro area spans the river.
• Northwest — South Dakota: Big Sioux River (north) and survey line. Sioux City (IA)/North Sioux City (SD) form cross-border community.

Geographic Significance

Iowa's borders are unusually river-defined (Mississippi east, Missouri west, Big Sioux northwest)—reflecting its position between two major watersheds. The northern and southern survey lines follow the 1846 Iowa Constitution boundaries adjusted during statehood (1846).

Tri-State Points

• IA-MN-WI: Mississippi River confluence near New Albin
• IA-IL-MO: Mississippi/Des Moines confluence near Keokuk
• IA-NE-SD: Missouri/Big Sioux confluence at Sioux City

These borders frame Iowa's identity as a transitional zone—between eastern forests and western prairies, northern lakes and southern plains—shaping its agriculture, settlement patterns, and political character.