[3] The county was created from Perry County in 1908 and named in honor of Nathan Bedford Forrest, a Confederate general in the American Civil War and the first Grand Wizard of the Ku Klux Klan.

Forrest County is part of the Hattiesburg, MS Metropolitan Statistical Area.

[4] As of the 2020 United States census, there were 78,158 people, 27,340 households, and 15,633 families residing in the county.

Forrest County has not supported the National Democratic ticket for president since 1944, when it voted overwhelmingly for Franklin Roosevelt in his landslide record fourth term victory.

Only twice since then has it not voted Republican, in 1948 when it backed the States Rights ticket of Strom Thurmond and then-Mississippi Governor Fielding Wright, and in 1968 when it voted for George Wallace and Curtis LeMay.