The Northumberland County Historical Society was established in 1925 by a group of interested and dedicated county citizens.It is the oldest historical society in the county, and the only one officially recognized by the County Board of Commissioners.It is a tax exempt, not-for profit 501(c)3 organization.

The Society's mission is to promote an interest in, and an appreciation of Northumberland County history by collecting, preserving, and researching the material culture of the County through its museum; by encouraging genealogical and local history research through its library; and by publishing a series of Proceedings, genealogical papers, walking tours of the historic districts of cities and towns inthe County, as well as miscellaneous occasional publications.