The Cypress Street Viaduct, often referred to as the Cypress Structure or the Cypress Freeway, was a 1.6-mile-long (2.5 km), raised two-deck, multi-lane (four lanes per tier) freeway constructed of reinforced concrete that was originally part of the Nimitz Freeway (State Route 17, and later, Interstate 880) in Oakland, California. It replaced an earlier single-deck viaduct constructed in the 1930s as one of the approaches to the San Francisco–Oakland Bay Bridge. It was located along Cypress Street between 7th Street and Interstate 80 in the West Oakland neighborhood.