A Colonial Conflict That Resulted in the Maryland-Pennsylvania Border

In ‘This Week in History,’ a royal geographical error in the colonies leads to a border war that ultimately results in the famous Mason-Dixon Line.

Mason-Dixon Line on U.S. Route 11 between Hagerstown, Md. and Greencastle, Pa. Photo by T.W. Kines, August 1949. Public Domain

George Calvert, Lord Baltimore, requested a charter to begin a colony in the New World. The request was approved by King Charles I in 1632. There is no doubt that Calvert would have been pleased at the news of the approval had he still been alive. Ironically, he died the same year the charter was approved.

The charter, which established the colony’s boundaries between the Atlantic Ocean and Chesapeake Bay with the 40th parallel as its northern border, therefore, went to his eldest son, Cecil, Second Lord Baltimore.