Auburn is a city in Lee County, Alabama, United States. It is the largest city in eastern Alabama. The population was 76,143 at the 2020 cens…Auburn is a city in Lee County, Alabama, United States. It is the largest city in eastern Alabama. The population was 76,143 at the 2020 census. It is a principal city of the Auburn-Opelika Metropolitan Area. The Auburn-Opelika, AL MSA with a 2020 population of 193,773, along with the Columbus, GA-AL MSA and Tuskegee, Alabama, comprises the greater Columbus-Auburn-Opelika, GA-AL CSA, a region home to 563,967 residents as of 2020.