The Historical Society of Port Jefferson 115 Prospect St, Port Jefferson, NY11777 The Historical Society of Greater Port Jefferson was formed to preserve the history of Port Jefferson by finding out…More facts and information and displaying items of interest related to the town and its history. The society is based in The Mather House Museum and is responsible for the extensive collection of local artifacts on display. It also holds special exhibits, meetings and fundraisers throughout the year to support the cause. The website offers information about the history of Drowned Meadow, the original name of Port Jefferson before it was changed to honor then-President Thomas Jefferson. It also has self-guided walking tours you can view and print on the website.