The family Protocetidae was first delimited to include Protocetus and Eocetus, the only protocetid genera known at that time. Both are from the middle Eocene of Gebel Mokattam, Egypt. Only three genera were added to the family prior to the 1990s, but since then 16 genera from Indo-Pakistan, North and West Africa, and North America have been added, greatly expanding our knowledge of their diversity, anatomy, behavior, and biogeography. Protocetids are as yet unknown from Europe, Oceania, the North Pacific, or Antarctica. Here, several protocetid teeth are described from New Jersey and South Carolina. The New Jersey specimens represent the northern-most discovery of protocetids in the world. Several were collected by avocational paleontologists, while others were identified in museum collections, where they were previously misidentified. Currently, there are four protocetid species from North America, each in its own genus: Carolinacetus gingerichi, Crenatocetus rayi, Georgiacetus vogtlensis, and Natchitochia jonesi.