According to the United States Census Bureau, the town has a total area of 52.8 square miles (136.8 km2), of which, 40.9 square miles (106.0 km2) of it is land and 11.9 square miles (30.8 km2) of it (22.53%) is water. Bourne is bordered by Sandwich to the east, Falmouth to the south, Wareham to the west, and Plymouth and Cape Cod Bay to the north. The town lies approximately twenty miles west of Barnstable, fifty-five miles south-southeast of Boston, and equidistantly from Providence, Rhode Island. The border with Plymouth and Wareham in Plymouth County constitutes the only landed border between Barnstable County and any other county (the borders with Dukes and Nantucket lie in Nantucket Sound). Major localities of Bourne include Bournedale and Buzzards Bay on the West side of the Cape Cod Canal, Sagamore, which straddles the canal, Bourne village, Monument Beach, Pocasset, and Cataumet on the East side of the canal
