Carolinacetus is an extinct protocetid early whale found in the Bartonian (40.4 to 37.2 mya) Tupelo Bay Formation (33°18′N 79°42′W / 33.3°N 79.7°W, paleocoordinates 33°18′N 70°54′W / 33.3°N 70.9°W) in Berkeley County, South Carolina. Carolinacetus is known from an incomplete cranium with portions of the right inner ear, a detached rostrum, and parts of both mandibles with 11 teeth. Preserved from the postcranium are 13 vertebrae and 15 ribs. The holotype was collected in 1994.