The completion of the nearby interstate highway 95 offered convenient access for visitors from the major markets between New York and Boston. By 1968—the year the Museum was featured in National Geographic Magazine—more than half a million visitors arrived. During this period of expansion the Planetarium, Seamen’s Inne, Mildred C. Mallory Memorial Membership Building, G.W. Blunt White Library, and the expanded Museum store were opened. In 1964, the fishing schooner L.A. Dunton joined the Museum’s fleet of historic vessels.
With such success came fears of overextension, especially as the growing fleet of large vessels exceeded the Museum’s ability to care for them. The small shipyard and marine railway opened in 1957 could not keep up with the needed work. The ferryboat Brinckerhoff, which had come in 1950, was let go in 1961. The Australia was hauled ashore for work in 1961 and never returned to the water. Additional vessels were passed on to other organizations to reduce the size of the growing fleet.
- 14 May — Planetarium opens. Mystic River Diorama (scale model) construction begins.
- Fall — Beginning of local school sailing classes.
- Opening of Doctor’s Office, Hoop Shop, Print Shop, and Weave Shop exhibits.
- Rachael Carson’s Silent Spring published.
- September — L.A. Dunton purchased in Grand Bank, Newfoundland.
- Male exhibit staff costumed for the first time on Museum grounds.
- Almost 3,000 visiting boats tie-up at the Museum during the summer.
- Cooperage exhibit opens.
- Charles W. Morgan becomes a Registered National Historic Landmark.
- Mystic Seaport featured in National Geographic Magazine.
- New Shoreham Life-Saving Station arrives by barge from Block Island, RI.
- Museum President Waldo Johnston travels to Europe and Scandinavia to observe ship preservation techniques.