Philadelphia 's only accessible and intact #UndergroundRailroad Station. | ☎️ 215-438-1768 Mission: The Johnson House Historic Site, a Center Social Advocacy, is a historic house museum that represents what everyday people have done and can do to make a difference in their community and beyond. The example of partnership—between Africans seeking freedom and the abolitionist Johnson family—serves as a catalyst to inspire, uplift and empower current and future generations. We accomplish these goals by creating interactive educational opportunities, fostering community initiatives and preserving the historic integrity of the house, grounds and outlier buildings.