Hattiesburg is a city in the U.S. state of Mississippi, located primarily in Forrest County and extending west into Lamar County. The city population was 48,730 in 2020, making it the 5th most populous city in Mississippi. Hattiesburg is the principal city of the Hattiesburg Metropolitan Statistical Area, which encompasses Covington, Forrest, Lamar, and Perry counties. The city is the anchor of th…