Fallout: The Pennsylvania War takes place in southern Pennsylvania, in the area where PDI and The Principality of Quebec are in contact, during the years of 2277 and 2278. It follows the experiences of The Dutchman during the PDI-Quebec war.
The game takes place in a large chunk of southern Pennsylvania and a small portion of northern Maryland. Compared to the Capital Wasteland and New York, Pennsylvania is still relatively alive and lush, and is capable of supporting old-fashioned agriculture in the "Dutch Country". It focuses around the clash between Quebec and PDI, although it also has some focus on the Amish and their post-war way of life.