[2] Its name derives from a town of the Creek tribe and the Coosa River, which forms one of the county borders.

Coosa County is included in the Talladega-Sylacauga, AL Micropolitan Statistical Area, which is also included in the Birmingham-Hoover-Talladega, AL Combined Statistical Area.

As of the 2020 United States census, there were 10,387 people, 4,032 households, and 2,657 families residing in the county.

As of the census[12] of 2010, there were 11,539 people, 4,794 households, and 3,293 families living in the county.

27.9% of all households were made up of individuals, and 11.1% had someone living alone who was 65 years of age or older.

[13] Annette Jones Watters of the University of Alabama's Alabama State Data Center cited Coosa as one of eight counties to lose greater than 6% of its population from 2000 to early 2007.

24.30% of all households were made up of individuals, and 9.80% had someone living alone who was 65 years of age or older.

Coosa County is reliably Republican at the presidential level.

The last Democrat to win the county in a presidential election is Bill Clinton, who won it by a slim majority in 1996.