North American crayfishes are hosts for 2 major groups of obligate ectosymbionts, namely annelids of the order Branchiobdellida and ostracods of the family Entocytheridae. These symbionts are widely distributed across the continent, coincident with their typical hosts; however, the diversity and distribution of both groups are poorly known in much of the northeastern US. We examined 93 crayfishes collected from 30 sites across New England for the presence of branchiobdellidans and entocytherids. We recovered 4 branchiobdellidan and 3 entocytherid species, with both groups displaying curiously dissimilar distributions. We present here the first published records of the branchiobdellidan Cambarincola vitreus in New England, the first record of the Procambarus acutus (White River Crayfish) from New Hampshire, and begin to fill substantial gaps in the known distribution of 2 major groups of obligate crayfish ectosymbionts.