Lauderdale County is a county located on the eastern border of the U.S. state of Mississippi. As of the 2020 census, the population was 72,984. The county seat and largest city is Meridian. The county is named for Colonel James Lauderdale, who was killed at the Battle of New Orleans in the War of 1812. Lauderdale County is included in the Meridian, MS Micropolitan Statistical Area.