Birmingham Northern Beltline

Interstate 422 (I-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 2048. 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. The route was first conceived in the 1960s, but funding issues and pushback from environmental activists have stalled the project for decades with only a short, unused segment being constructed in the mid-2010s. A 10-mile-long (16 km) section between Gardendale and Pinson was funded in spring 2023, but the start of construction was delayed by another complaint before construction on the initial unused segment resumed in Summer 2024.

Current plans for the route have it connecting to I-59 at I-459's current southern terminus in Bessemer, at approximately milemarker 147 to the northeast of Trussville, near Argo. Additional studies are underway to determine the economic feasibility to continue the route from its proposed northeastern terminus southward to I-20 in the Leeds–Moody area in western St. Clair county.

The route has been designated as the Appalachian Regional Commission's high-priority Corridor X-1, unsigned State Route 959 (SR 959), and I-422.