The Custom House Maritime Museum was formerly the Newburyport Custom House that was built to facilitate the growing overseas trade and tax collection of imported goods on the waterfront. The building, designed by Robert Mills, features vaulted ceilings and cantilevered staircases.

When Newburyport declined as a commercial seaport, the Custom House was turned into a manufacturing site for shoes and a storage area for submarine parts before transforming into an impressive maritime museum, a research facility, an educational center, and a meeting place for professional and social gatherings. The Museum, housing maritime memoirs, artifacts, and other memorabilia, was established to protect, preserve, and communicate the maritime heritage of the Merrimack Valley and its role and contributions to society.

The Museum is available for custom tours and special events.