A handsome granite Greek Revival building at 150 Bank Street, built in 1833–35 and still in use as a federal customs office — one of the oldest continuously operating customs houses in the United States. The architect was Robert Mills, who also designed the Washington Monument, and the building has the solidity and restraint that characterise his work.
The Custom House Maritime Museum operates here, with exhibits on New London's whaling history, the port's role in the American Revolution, and the city's maritime heritage. The building's position near the waterfront places it at the centre of what was once one of the busiest ports on the Atlantic coast.