"The Newburyport Maritime Society (NMS) is is a non-profit organization dedicated to preserving and interpreting the maritime heritage of the lower Merrimack Valley. The NMS owns and operates the Custom House Maritime Museum in Newburyport and Lowell Boat Shop Museum in Amesbury. The building is not large, four rooms of each of two floors. Charges were very reasonable, $7 for adults, $5 for us oldsters. There was a different exhibit in each of the rooms ranging from the Coast Guard (founded in Newburyport), to a very interesting WWII ship model exhibit, to the history of the man who designed this and other customs houses in New England in the 1800s to a shipbuilding exhibit. It took us about an hour to go through the exhibits fairly carefully. Definitely a good way to spend an hour or so in Newburyport.