Aratus pisonii (Mangrove Tree Crab), an arboreal crab local to neotropical mangrove forests, has increasingly been observed in salt marshes north of its historically documented range. Vertical structures, like docks and break walls, are known to serve as habitat alternatives to mangrove trees, and may therefore facilitate the spread of Mangrove Tree Crabs in suboptimal salt marsh habitat. However, the role intertidal woody habitat plays in assisting the spread of this species has not been investigated. A survey of built and woody habitats on Sapelo Island, GA, revealed multiple Mangrove Tree Crab year classes at built sites, but near total absence in woody habitats. This study also offers the northernmost evidence for reproduction for this species, and it presents the first evidence of a Mangrove Tree Crab in woody habitat north of the mangrove range.