The Sigal Museum is one of four museums operated by the Northampton County Historical and Genealogical Society (the other three are historic homes). The museum serves as the county's main historical center and repository. Its collection contains items dating back hundreds of years to the present. These include Native American artifacts, agricultural tools, documents from the Great Treaty of 1758 (aka the Treaty of Easton; an agreement during the French and Indian War in which the Indian tribes agreed to not fight with the French in return for land lost), and other items. The archives contains thousands of books, photographs, documents and other materials.
The building itself was originally an opera house built in 1872. In 1957, Arthur Sigal bought it and renovated it for retail use, thereby erasing all vestiges of the former venue. The historical society bought the building in 2003 and proceeded to renovate it once more leading to its opening in 2010.