The State That Seceded From a State

West Virginia is the only state in the United States to have been formed by seceding from another state. When Virginia voted to leave the Union in April 1861, the counties of western Virginia, whose residents had little in common with the plantation culture of the eastern part of the state and who depended on the Union for trade, voted to reject secession. West Virginia was admitted to the Union as the 35th state on June 20, 1863, while the Civil War was still being fought, with its boundaries drawn through active combat zones.

Source: Wikipedia