Middlesborough, city (1990 pop. 11,328), Bell co., S Ky., in the Cumberland Mts. near the point where Kentucky, Tennessee, and Virginia meet; inc. 1890. It is a coal-mining center with meat and coal processing, leather tanning, and diverse manufacturing. Middlesborough is at the western portal of the Cumberland Gap Tunnel (completed 1996). Cumberland Gap National Historical Park (see National Parks and Monuments, table) and Pine Mt. are nearby.