The objectives of the Prince George's County Historical Society are:

• To foster an understanding and appreciation of the history and heritage of Prince George's County.
• The collection, recording, organization, restoration, and preservation of historical data, artifacts and all associated materials relative to Prince George's County and the state of Maryland.
• To promote and encourage research into all aspects of Prince George's County history and heritage.
• To acquaint and make available to members and the general public historical data and all associated materials relating to Prince George's County through programs and publications arranged or sponsored by the Society.
• To encourage and participate in the protection and preservation of historic sites and structures in Prince George's County.

The Society is headquartered in the historic Marietta Mansion. The Historical Society's library (the Frederick S. DeMarr Library of County History) has moved to the Greenbelt Public Library building at 11 Crescent Road in Greenbelt. After the official Grand Opening of the library on Saturday, May 31, 2008, hours for research will be noon to 4:00 p.m., and by appointment. Call 301-220-0330.

The Grand Opening starts at 1:00 p.m at the Community Center at 15 Crescent Road, next door to the library, and finishes with the ribbon cutting at the library at 11 Crescent Road.