The area of Pennsylvania was part of the original territory of the United States. It was chartered in 1681, although New York did not relinquish its claim to the area until the following year. The southern boundary was resolved with the survey of the Mason and Dixon Line in the 1760s. Connecticut had claims to Pennsylvania territory resolved by award of the Continental Congress in 1782. Pennsylvania ratified the U.S. Constitution on December 12, 1787; it was the second of the original 13 states to join the Union. Pennsylvania assumed generally the same boundary as the present state with the acquisition of the Erie Triangle from New York in 1792. Pennsylvania is one of four states that are legally described as a commonwealth.