Roslagens Sjöfartsmuseum, Älmsta

Roslagens sjöfartsmuseum is a maritime history museum at the old Kaplansbacken Älmsta, Norrtälje municipality.

The museum was founded in 1938 and is run by the Roslagens Sjöfartsminnesförening. Kaplansbacken was formerly the chaplain's residence of Väddö parish. A new extension was built in 2002 to accommodate the post office's boats. The museum also houses the Skeppargården, which was decorated as a farmer's home. The building is a former magistrate's court built in the mid-19th century and moved here from Häverö.

The museum displays exhibits on the maritime traditions of the rowing pig, including the Viking Age, sea mail and modern ferry traffic. Also on display are archipelago fishing, archipelago sailing, cargo barges, sails and steam, boatbuilding traditions, barges, timber towing and the service industries of shipping: lighthouse keeping, pilotage and sea rescue. The history of the Väddö Canal is also covered in the museum.