Throughout the geographic range, adult Eastern Massasaugas (Sistrurus catenatus) exhibit plasticity in movement, fecundity, diet, and activity range size; however, the ecology of subadults remains unknown. We attached radio transmitters to 16 free-ranging neonate S. catenatus and monitored their movements and growth for up to 56 days prior to their initial hibernation. Neonate movement frequency (70%) was consistent with values reported for adults throughout the geographic range, but activity range size (0.36 ha) and mean daily distance moved (5.3 m) were smaller. Males gained significantly more mass than females over the first 50 days, but no difference in length was detected. Neonate S. catenatus returned to their general birthing area to overwinter. Because of ontogenetic shifts and differences in the spatial distribution of resources, regionally-specific management plans based on data for all age classes are essential in providing effective conservation measures.