U.S. Route 121 (US 121) is a proposed U.S. highway designated as the Coalfields Expressway, a four-lane highway stretching from Beckley, West Virginia, to Pound, Virginia, approximately 108 miles (174 km) in length. It is designed to connect Interstate 64 (I-64) and I-77 in West Virginia near Beckley to US 23 in Wise County, Virginia, at Pound. While US 121 will not connect directly to US 21, it will intersect at the latter road's original alignment, now a part of I-77.

Beckley is a city in and the county seat of Raleigh County, West Virginia, United States. The population was 17,286 at the 2020 census, making it the ninth-largest city in the state. It is the principal city of the Beckley metropolitan area of Southern West Virginia, home to 115,079 residents in 2020. Beckley was founded on April 4, 1838, and was long known for its ties to the coal mining industry. It is the home of the West Virginia University Institute of Technology, as well as an annex of Concord University and the University of Charleston.