York County is a county in the U.S. state of Pennsylvania. As of 2010, the population was 434,972. It is in the Susquehanna Valley, a large fertile agricultural region in South Central Pennsylvania.
York County was created on August 19, 1749, from part of Lancaster County and named either for the Duke of York, an early patron of the Penn family, or for the city and shire of York in England. Its county seat is the city of York. Based on the Articles of Confederation having been adopted in York by the Second Continental Congress on November 15, 1777, the local government and business community began referring to York in the 1960s as the first capital of the United States of America. The designation has been debated by historians ever since. Congress considered York, and the borough of Wrightsville, on the eastern side of York County along the Susquehanna River, as a permanent capital of the United States before Washington, D.C., was selected.