It is named for the second President of the United States, John Adams, who held that office when the county was organized in 1799.

The county was organized eighteen years before Mississippi became a state.

Five Mississippi governors have come from Adams County: David Holmes, George Poindexter, John A. Quitman, Gerard Brandon, and William Allain.

[4] As of the 2020 United States Census, there were 29,538 people, 11,237 households, and 6,650 families residing in the county.

[15] This is adjacent to the Natchez campus of Alcorn State University.

Adams County Correctional Center, a private prison operated by the Corrections Corporation of America on behalf of the Federal Bureau of Prisons, is in an unincorporated area in the county.

After supporting Dixiecrat Strom Thurmond in 1948, it began to lean more Republican, and remained that way until the 1980s.