Where is Adair County?

4 Adair Counties in 4 states · 72,338 people (2025)

There are 4 counties named Adair County in the United States, in Iowa, Kentucky, Missouri and Oklahoma. The most populous is Adair County, Missouri (county seat: Kirksville), with 25,684 people in 2025. 3 of them are named after John Adair, American politician (1757–1840).

Map of the United States showing where all 4 Adair Counties are, labeled by state
Every Adair 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 4 Adair Counties

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

StateCounty seatPopulation 2025Land area (sq mi)EstablishedNamed after
Adair County, IowaGreenfield7,4035691851John Adair
Adair County, KentuckyColumbia19,4234051802John Adair
Adair County, MissouriKirksville25,6845671841John Adair
Adair County, OklahomaStilwell19,8285741907William Penn Adair

Questions about Adair Counties

How many Adair Counties are there?

There are 4 Adair Counties in the United States, in Iowa, Kentucky, Missouri and Oklahoma.

Which Adair County is the largest?

By population, Adair County, Missouri (25,684 people in 2025). By land area, Adair County, Oklahoma (574 sq mi).

Which Adair County is the oldest?

Adair County, Kentucky, established in 1802. The newest is Adair County, Oklahoma (1907).

Why are there so many Adair Counties?

3 of the 4 are named after John Adair, American politician (1757–1840). Many counties took their names from the same founders, presidents and generals as new states were organized.

How do I find out which Adair 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