Larval habitats of salt marsh Culicoides spp. were delineated. Twenty-six habitat categories were equally sampled. Four broad physiographic zones were identified from aerial photographs and ground surveys. Two salt marsh zones were identified and separated on the basis of differences in plant cover type and distribution, number and conformation of islands, tidal creeks and ponds, and substrate structure. The other 2 zones were an extensive brackish-freshwater marsh and an upland area dominated by mixed pine and live oak. The more frequently flooded salt marsh zone provided the most productive Culicoides larval habitats. Data obtained from samples held for adult emergence indicated that C. mississippiensis was largely confined to these lower elevation marsh areas, but C. furens was found in both salt marsh and freshwater habitats.