Explore Interstate 270, a network of vital auxiliary highways serving key metro areas including St. Louis, Washington, D.C., Columbus, and Denver. Learn about its routes, major interchanges, and regional importance.
Interstate 270 (I-270) is the designation for several auxiliary Interstate highways in the United States, each serving as a bypass or connector route around major cities. The two most prominent stretches of I-270 are located in Missouri/Illinois and the Washington, D.C. metropolitan area, with additional shorter segments in Colorado and Ohio.
In the St. Louis region, I-270 forms a partial beltway that loops around the northern and western suburbs of the city. This route begins at I-55 in Mehlville (south of St. Louis) and arcs clockwise through several major junctions—intersecting I-44, I-64, I-70, and I-170—before merging into I-255 near Pontoon Beach, Illinois. This corridor is heavily traveled and known for its congestion, especially near major commercial hubs and river crossings.
Another major segment of I-270 is in the Washington, D.C. area, where it begins in Bethesda, Maryland, as a busy spur from the Capital Beltway (I-495) and extends northwest to Frederick, Maryland, where it connects with I-70. This route serves as a critical commuter artery for the Maryland suburbs and plays a significant role in linking the capital region with the rest of the Northeast corridor.
Smaller versions of I-270 exist in Columbus, Ohio—where it forms a full loop around the city—and in the Denver, Colorado area, where it connects I-25 with I-70 via a short but vital industrial corridor.
Take a 14-mile drive on Interstate 270 South from Bridgeton to St. Louis, Missouri. Explore key interchanges, local attractions like Creve Coeur Lake, and see why I-270 is a crucial bypass route in the St. Louis metro area. Includes route map and points of interest.
Travel west along Interstate 270 in St. Louis, Missouri, from the Chain of Rocks Bridge to Bridgeton. Explore historic suburbs, major interchanges, and evolving infrastructure on this 15-mile urban loop.
Take a scenic drive along Interstate 270 from Bethesda to Frederick, Maryland. Explore busy suburbs, Civil War history, and open farmland on this 31-mile route through the Washington National Pike.