The area of Kentucky was originally part of Virginia within the original United States. Virginia ceded the district of Kentucky to the United States in 1792, and this area was included briefly in the Southwest Territory ("territory ... south of the Ohio River"). Kentucky was admitted to the Union on June 1, 1792, as the 15th state. Upon resolution of a boundary dispute with Tennessee in 1820, Kentucky assumed generally the same boundary as the present state. Kentucky is one of four states that are legally described as a commonwealth.