pass in the Cumberland Plateau, at the juncture of the Va., Ky., & Tenn. borders: c. 1,700 ft (518 m) high
See Cumberland Gap in American Heritage Dictionary 4
Cum·ber·land Gap
A natural passage through the Cumberland Plateau near the junction of the Kentucky, Virginia, and Tennessee borders. It was used by Daniel Boone in 1775 as a strategic point along his Wilderness Road, the principal route of westward migration for the next half century.