Columbus is a consolidated city-county located on the west-central border of the U.S. state of Georgia. Columbus lies on the Chattahoochee River directly across from Phenix City, Alabama. It is the county seat of Muscogee County, with which it officially merged in 1970. Columbus is the second-largest city in Georgia (after Atlanta), and fields the state's fourth-largest metropolitan area. At the 2020 census, Columbus had a population of 206,922, with 328,883 in the Columbus metropolitan area. The metro area joins the nearby Alabama cities of Auburn and Opelika to form the Columbus–Auburn–Opelika Combined Statistical Area, which had an estimated population of 486,645 in 2019.