The area of Maryland was part of the original territory of the United States. It was chartered as a colony in 1632. The area described by this charter, however, conflicted with the charter for Virginia and, later, the charter for Pennsylvania. Virginia relinquished its claims in 1658, and the Pennsylvania boundary was resolved with the survey of the Mason and Dixon Line in the 1760s. Maryland ratified the U.S. Constitution on April 28, 1788; it was the seventh of the original 13 states to join the Union. Its area was reduced with the cession in 1788 and formation in 1791 of the District of Columbia, resulting in generally the same boundary as the present state.