Clay County is a county located in the southwestern part of the U.S. state of Georgia. As of the 2020 United States census, the population was 2,848, making it the third-least populous county in Georgia. The county seat is Fort Gaines.

This area was historically occupied by the Creek Indians until Indian Removal in the 1830s. European Americans pushed them out and developed the land for cotton, bringing in thousands of African slaves to work the land.

The county is named in honor of Henry Clay, famous American statesman, member of the United States Senate from Kentucky and United States Secretary of State in the 19th century. Part of the Black Belt geological formation of Georgia, prior to the American Civil War the county's chief commodity crop was cotton, cultivated and processed by farmers and African-American slaves. After the war, the economy continued to be agricultural, but timber was also harvested.

Clay was created by a February 16, 1854, act of the Georgia General Assembly, and organized from portions of Early and Randolph counties.

Clay County's population is one-third of what it was in 1910.

According to the U.S. Census Bureau, the county has a total area of 217 square miles (560 km²), of which 195 square miles (510 km²) is land and 22 square miles (57 km²) (10.1%) is water.

The central and southwestern portions of Clay County, from west of Bluffton to northwest of Coleman, are located in the Lower Chattahoochee River sub-basin of the ACF River Basin (Apalachicola-Chattahoochee-Flint River Basin). The county's northwestern corner, which is bisected by State Route 39 running north from Fort Gaines, is located in the Middle Chattahoochee River-Walter F. George Lake sub-basin of the same ACF River Basin. Just the very southeastern corner of Clay County is located in the Spring Creek sub-basin of the same larger ACF River Basin.

As of the 2020 United States census, there were 2,848 people, 1,242 households, and 708 families residing in the county.