Glen Allan is an unincorporated community located in far southern Washington County, Mississippi. It is situated immediately east of Lake Washington's southern shore.
Although it is unincorporated, it has a post office, with the ZIP code of 38744.
Glen Allan is served by the Western Line School District. The elementary schools are O'Bannon Elementary and Riverside Elementary. The High Schools are O'Bannon High and Riverside High School.
Glen Allan is the birthplace of author Clifton Taulbert and blues guitarist/singer songwriter Robert Lee "Smokey" Wilson.
Coordinates: 33°01′26″N 91°01′48″W / 33.02389°N 91.03000°W