Interstate 422, Corridor X-1, or the Birmingham Northern Beltline is a proposed 52.5-mile-long (84.5 km) northern bypass route around Birmingham, Alabama, through northern and western Jefferson county that is projected to be completed by 2054. Along with the existing I-459, the Northern Beltline would complete the bypass loop of central Birmingham for all Interstate traffic. The project's budget is $5.445 billion; upon completion, the Northern Beltline will be the most expensive road in Alabama's history, and among the most expensive per-mile ever built in the United States.