Three species of harpacticoid copepods are newly reported from long- and short-hydroperiod groundwater and surface freshwater habitats in Everglades National Park, Florida, U.S.A. One is new to science and described herein; Nitokra evergladensis, new species, differs from congeners mainly in details of setation and spination of the endopodites of the swimming legs, the ornamentation of the anal operculum, and the shape and setae of the caudal ramus. Records of members of the genus Nitokra in fresh waters in the U.S.A. are reviewed, and a key to their identification is presented. We present a supplementary description of Attheyella americana, a widespread species previously unrecorded in southern Florida, based on material from the Everglades. Collections of the rare species Bryocamptus newyorkensis in the Everglades have extended its distribution considerably southward. We redescribe both sexes on the basis of specimens collected from Everglades National Park and also from Great Smoky Mountains National Park, Tennessee, and discuss the geographical distribution and habitats of the species. The Everglades “freshwater” harpacticoid fauna is depauperate, having a large proportion of species adapted to marine habitats.