Where is Buchanan County?

3 Buchanan Counties in 3 states · 122,915 people (2025)

There are 3 counties named Buchanan County in the United States, in Iowa, Missouri and Virginia. The most populous is Buchanan County, Missouri (county seat: St. Joseph), with 83,540 people in 2025. 3 of them are named after James Buchanan, president of the United States from 1857 to 1861.

Map of the United States showing where all 3 Buchanan Counties are, labeled by state
Every Buchanan County in the United States (red), labeled with its state. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).

All 3 Buchanan Counties

Sorted by state. Each link opens the county's map.

StateCounty seatPopulation 2025Land area (sq mi)EstablishedNamed after
Buchanan County, IowaIndependence20,8835711837James Buchanan
Buchanan County, MissouriSt. Joseph83,5404081838James Buchanan
Buchanan County, VirginiaGrundy18,4925031858James Buchanan

Questions about Buchanan Counties

How many Buchanan Counties are there?

There are 3 Buchanan Counties in the United States, in Iowa, Missouri and Virginia.

Which Buchanan County is the largest?

By population, Buchanan County, Missouri (83,540 people in 2025). By land area, Buchanan County, Iowa (571 sq mi).

Which Buchanan County is the oldest?

Buchanan County, Iowa, established in 1837. The newest is Buchanan County, Virginia (1858).

Why are there so many Buchanan Counties?

3 of the 3 are named after James Buchanan, president of the United States from 1857 to 1861. Many counties took their names from the same founders, presidents and generals as new states were organized.

How do I find out which Buchanan County an address is in?

Open the county map of the state: it has a search box for cities, towns and ZIP codes. On a phone, the "what county am I in" tool on our sister site uses your location.

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Other common county names