Mapping Pennsylvania History uses original historic and large reproduction maps to trace the growth of the state and the city of Philadelphia, the Native American presence (according to the maps), and significant historical events, such as Washington’s encampments in Montgomery County. We’re focusing on maps that illustrate southeastern Pennsylvania from the colonial period to the early 1900s. Do you live in a historic house in the Philadelphia suburbs? See if you can locate it on the large 1865 wall map (portions pictured) that we have on view.