U.S. Route 121, is a planned highway designated as the Coalfields Expressway, a four lane freeway stretching from Beckley, West Virginia to Pound, Virginia. It is designed to join Interstate 77/Interstate 64 in West Virginia close to Beckley to U.S. Route 23 in Wise County, Virginia at Pound.
While U.S. 121 won't connect directly to U.S. Route 21, it will interconnect at the latter road's original alignment, currently a part of I-77.