Northern diamondback terrapins, Malaclemys terrapin terrapin, were tagged with passive integrated transponder tags to mark them and monitor their activity along a road through salt marsh habitat in Tuckerton, New Jersey. A mark-recapture study was conducted to evaluate terrapin movements, nesting frequency, and nest site fidelity. During sampling periods throughout 2 nesting seasons (2004–2005), 300 adult females were tagged. Ninety-two recaptures were made of 54 individual terrapins, with most recaptures (81.5%) occurring within a season (range = 1–45 days, mean = 7.5 days). Some recaptures (18.5%) occurred the following year. Some females crossed the road multiple times during nesting, and nearly half searched for a site within 50 m of the area where they were initially tagged. Nest site selections of all multiple nesters (within and among seasons) varied greatly from approximately 4–1307 m (mean internesting distance = 202.75 m), yet 39% were recaptured within 50 m of their initial tagging location. One-third of yearly nesters showed an internesting distance within 25 m of their initial-year tagging location. These results indicate that some females travel variable distances between nest sites and may demonstrate evidence of nest site fidelity.