The Kingwood Tunnel was constructed on the Baltimore & Ohio Railroad between 1849 and 1852 near Tunnelton, in Preston County. The tunnel was named for nearby Kingwood, and Tunnelton was named for the tunnel. The tunnel's completion allowed the completion of the B&O across Western Virginia to Wheeling. During the Civil War, the Confederates tried unsuccessfully to destroy the tunnel during the Jones Imboden Raid of 1863.

The Kingwood Tunnel was one of many tunnels and bridges that engineers had to design to bring the B&O through Western Virginia's mountainous terrain. The tunnel was constructed by a work force composed primarily of Irish immigrants working with simple tools. The workers tunneled on each end, with three additional shafts being constructed from the top of the hill. Temporary railroad tracks were laid to transport supplies over the mountain during construction. The tunnel measured nearly 4,100 feet in length and required the movement of nearly 200,000 cubic yards of earth and rock. At the time it was reputedly the longest rail tunnel in the world.

A major problem with the Kingwood Tunnel was its design as a single-track tunnel, which made it a chronic bottleneck. A new double-track tunnel was completed in 1912 below the original tunnel to help alleviate train congestion in the area. The original tunnel was closed and sealed in 1962.