Carolinacetus is an extinct protocetid early whale found in the Bartonian (40.4 to 37.2 mya) Tupelo Bay Formation (33.3°N 79.7°W / 33.3; -79.7, paleocoordinates 33.3°N 70.9°W / 33.3; -70.9) 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.