The Chatham Historical Society was organized in 1923. Three years later, the society acquired the Atwood House - a gambrel-roofed house built in 1752. Except for the addition of essential electricity, the old Atwood House is unchanged from when it was built and is furnished throughout as it was during the 18th and 19th centuries. Over the years, museum galleries have been added to the original structure without affecting its integrity. As a result of the major expansion and renovation to the museum completed in 2005, there are now eleven galleries with both permanent exhibits and temporary exhibits.
On the grounds are the mid-20th century Nickerson North Beach Camp, the Chatham School Bells display, and the Chatham Light Display, featuring the lantern house from Chatham’s twin light with its original Fresnel lens, which flashes its beam whenever the museum is open.