Monroe is a city and the county seat of Walton County, Georgia, United States. It is located both one hour east of Atlanta via US 78 and GA 138 to I-20 and east of Hartsfield–Jackson International Airport and is one of the exurban cities in the Atlanta metropolitan area. The population was 14,928 at the 2020 U.S. census.

State Route 138 (SR 138) is a 59.2-mile (95.3 km) state highway in the northwestern part of the U.S. state of Georgia. The highway is a west-to-east route that travels within portions of Fulton, Fayette, Clayton, Henry, Rockdale, Newton, and Walton counties that connects Fairburn and Monroe, while bypassing Atlanta.