The round-tailed muskrat (Neofiber alleni) is a species of rodent in the family Cricetidae, sometimes called the Florida water rat.

The round-tailed muskrat is a semiaquatic and nocturnal species native to the southeastern United States.

[6] This distribution is consistent with round-tailed muskrat fossils found in several Florida locations from the late Pleistocene.

[3] Large, high-quality wetland habitats in Florida and southeastern Georgia that have well-connected patches are preferred.

[10] Round-tailed muskrats have been described to be social mammals, but it has been suggested that they may live in colonies only when a shortage of suitable habitat occurs.