According to the
U.S. Census Bureau, the parish has a total area of , of which is land and (1.1%) is water. Jefferson Davis Parish comprises five incorporated towns including Elton, Fenton, Jennings, Lake Arthur, and Welsh. There are also many unincorporated areas that add to the interest and economic structure of the parish including Barnsdall, Buller, China, Coverdale, Edna, Fontenot, Foreman's Hall, Hathaway, Illinois Plant, Lacassine, Lauderdale, Panchoville, Pine Island, Raymond, Roanoke, Silverwood, Thornwell, Topsy, Verret, and Woodlawn.
Interstate 10 runs east and west through the center of the parish, providing access to local markets. Additionally, the
Union Pacific Railroad is centrally located within the parish and the
Mermentau River, which connects to the
Intracoastal Waterway and has a channel depth of nine feet, provides access to the Port of Mermentau. The Jennings Airport, with a runway length of , is capable of landing a small jet and is located next to Interstate 10. Jefferson Davis Parish also attracts sportsmen to the
Lacassine National Wildlife Refuge.
Adjacent parishes •
Allen Parish (north) •
Evangeline Parish (northeast) •
Acadia Parish (east) •
Vermilion Parish (southeast) •
Cameron Parish (south) •
Calcasieu Parish (west) •
Beauregard Parish (northwest) ==Transportation==