U.S. Route 50 or U.S. Highway 50 (US 50) is a major east-west route of the U.S. Highway system, stretching from Interstate 80 (I-80) in West Sacramento, California, to Maryland Route 528 (MD 528) in Ocean City, Maryland, on the Atlantic Ocean. Until 1972, when it was replaced by Interstate Highways west of the Sacramento area, it extended (by way of Stockton, the Altamont Pass, and the Bay Bridge) to San Francisco, near the Pacific Ocean. The Interstates were constructed later and are mostly separate from this route. It generally serves a corridor south of I-70 and I-80 and north of I-64 and I-40.