The genus Castanea, divided into seven extant species of trees worldwide, includes the American chestnut, C. dentata. This once common North American tree has been nearly eliminated from the landscape due to the appearance of chestnut blight early in the Twentieth Century. Castanea has a long history as a component of palynological assemblages, though megafossil paleobotanical remains are quite rare. The distributions of what are believed to be Castanea pollen as they have been derived from coastal plain and near-shore sediments dating back to the Neogene of the coastal plain of the southeastern US are discussed. The abundances of Castanea pollen in microfossil preparations are carefully considered relative to the concept of ‘pollen sum’ and while it appears that the trees were quite abundant as components of coastal woodlands during the Neogene, the actual number of pollen we found in samples is quite low. American chestnut trees continued to be important into the late Pleistocene and through the time when humans first occupied both coastal and inland areas of the southeastern US.