The Historical Society was founded as a non-profit educational corporation in January 1961. It opened a museum in what is now called the Heritage House at 0310 Third Street on March 3, 1963, near the start of Lewiston's Centennial Year. In 1974, the museum and offices of the Society moved “next door” to its present building at 0306 Third Street. The building was constructed as a Roosevelt's (WPA) Works Progress Administration project for the State of Idaho Department of Public Assistance in 1937. The building's architectural style is 1930s art deco.
The Historical Society is first and foremost a museum organization. The board of directors and staff are dedicated to the collection, preservation and dissemination of the history of Nez Perce County and the surrounding area, to the preservation of historical items and actively seek to expand the collection. In addition to preserving artifacts, the Society maintains a research library of Nez Perce County history and works with the public to provide educational information. A fine photograph collection consists of early day citizens as well as scenes of historic value. Prints of photographs can be obtained through the Society; a percentage of print charges helps to maintain an acid-free environment for the photograph and archival collections.