U.S. Senator John Snyder Carlile (December 16, 1817 - October 24, 1878) played a controversial role in the creation of West Virginia. He was born in Winchester, Virginia, in modest circumstances. He was educated by his mother and started out clerking in a store. He began studying law and was admitted to the bar in 1840. Setting up his practice in Beverly, which was then the county seat of Randolph County, he later moved to Philippi, then to Clarksburg. In 1847, he was elected to the Virginia Senate, beginning an eventful political career. He served also in the Virginia constitutional convention of 1850-51, and in Congress from 1855 to 1857 and from March until July 1861. In early 1861, he was a delegate to the secession convention in Richmond, where he and other delegates from the western counties bitterly opposed Virginia's secession from the United States.

When the convention nonetheless approved secession, Carlile returned home to Clarksburg to lead the movement toward a separate state. Immediately following his return from Richmond, Carlile organized the Clarksburg Convention, which called for a meeting in Wheeling the following month. He helped organize the resulting First Wheeling Convention in May 1861, which favored statehood but adopted a "wait and see" attitude toward Virginia's secession referendum. After Virginia voters approved secession in the subsequent statewide referendum, the Second Wheeling Convention in June established the Reorganized Government of Virginia, which would maintain a pro-Union government for Virginia throughout the Civil War. It was Carlile's "Declaration of the People of Virginia,", adopted by the convention, that called for the creation of this government. Carlile and Waitman T. Willey were elected as Virginia members of the U.S. Senate by the new Unionist state legislature.

In the summer of 1862, when the Senate began considering admission of West Virginia to the union, Carlile's actions took a controversial turn. He insisted upon a referendum among the people of the proposed new state before statehood could be approved. Given the Confederate sympathies in several southern and eastern counties, this might have derailed statehood. Eventually, a substitute bill written by Senator Willey was passed, which required only the approval by a constitutional convention. Many of Carlile's former friends now angrily viewed him as a traitor to the cause of statehood, and there were calls to have him impeached. However, he continued to serve in the U.S. Senate until March 3, 1865.

Carlile's political career was effectively ended. President Grant later nominated him as ambassador to Sweden, but the U.S. Senate refused to confirm him. Carlile died in Clarksburg and is buried in the Odd Fellows Cemetery.