Oak Grove is a census-designated place and unincorporated community located in Lamar County, Mississippi, United States.

[3] Oak Grove experienced a growth in its population beginning in the 1970s as families from nearby Hattiesburg moved to the community.

Schools, churches, businesses and newspapers were established, as were "the seeds of a long-running dispute about incorporation versus annexation by Hattiesburg".

[4] In 1987, the city of Hattiesburg filed a petition seeking to expand its corporate boundaries into Oak Grove.

Testimony at the appeal included the following: If you look at a map, the political boundaries removed, you will think Oak Grove a part of Hattiesburg.