Peachtree City is the largest city in Fayette County, Georgia, United States. As of the 2010 census it had a population of 34,364. Peachtree City is located in South Metro Atlanta. According to the U.S. Census Bureau, Peachtree City has a total area of 25.4 square miles (65.9 km2), of which 24.6 square miles (63.6 km2) is land and 0.93 square miles (2.4 km2), or 3.57%, is water. The city is in the watershed of Line Creek, which forms the western city boundary and county line, and is a south-flowing tributary of the Flint River.