Adair County is a county in the U.S. state of Iowa. As of the 2020 census, the population was 7,496. Its county seat is Greenfield.

John Adair was an American pioneer, slave trader, soldier, and politician. He was the eighth Governor of Kentucky and represented the state in both the U.S. House and Senate. A native of South Carolina, Adair enlisted in the state militia and served in the Revolutionary War, during which he was twice captured and held as a prisoner of war by the British. Following the War, he was elected as a delegate to South Carolina's convention to ratify the United States Constitution.