Interstate 880 (I-880) is an Interstate Highway in the San Francisco Bay Area connecting San Jose and Oakland, running parallel to the eastern shore of San Francisco Bay. For most of its route, I-880 is officially known as the Nimitz Freeway, after World War II fleet admiral Chester Nimitz, who retired to the Bay Area and lived on Yerba Buena Island.
The southern terminus of I-880 is at its interchange with Interstate 280 and State Route 17 in San Jose. From there, it heads roughly northeast past the San Jose International Airport to U.S. Route 101. The Nimitz Freeway then turns northwest, running parallel to the southeastern shore of San Francisco Bay, connecting the cities of Milpitas, Fremont, Newark, Union City, Hayward, and San Leandro before reaching Oakland. In Oakland, I-880 passes by Oakland International Airport, Oakland–Alameda County Coliseum and Downtown Oakland. The northern terminus of I-880 is in Oakland at the junction with Interstate 80 and Interstate 580 (known as the MacArthur Maze), near the eastern approach of the Bay Bridge.
I-880 between I-238 in San Leandro and the MacArthur Maze is used as an alternate truck route; trucks over 4.5 tons are prohibited through Oakland on I-580.
I-880 is part of the California Freeway and Expressway System, and is part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration. Officially, the Nimitz Freeway designation is Route 880 from Route 101 to Route 80, as named by Senate Concurrent Resolution 23, Chapter 84 in 1958.
The state legislature added the proposed San Jose-Richmond East Shore Highway to the state highway system in 1933, and it became an extension of the previously short (San Rafael to the bay) Legislative Route 69, and part of Sign Route 13 (soon changed to 17) in 1934. From San Jose, this route temporarily followed existing Legislative Route 5 (present Oakland Road, Main Street, Milpitas Boulevard, and Warm Springs Boulevard) to SR 21 at Warm Springs, and then continued along existing county roads and city streets, now known as Fremont Boulevard, Alvarado Boulevard, Hesperian Boulevard, Lewelling Boulevard, Washington Avenue, 14th Street, 44th Avenue, 12th Street, 14th Avenue, 8th Street, and 7th Street, into downtown Oakland. It then turned north at Cypress Street (now Mandela Parkway), passing through the Bay Bridge Distribution Structure and following a newly constructed alignment (signed as US 40) to El Cerrito.
The first short piece of the new Eastshore Freeway opened to traffic on July 22, 1949, connecting Oak Street downtown with 23rd Avenue. It was extended to 98th Avenue on June 1, 1950, Lewelling Boulevard on June 13, 1952, and Jackson Street (SR 92) on June 5, 1953. At the San Jose end, the overlap with Route 5 between Bayshore Highway (US 101) and Warm Springs was bypassed on July 2, 1954. Within Oakland, the double-decker Cypress Street Viaduct opened on June 11, 1957, connecting the freeway with the San Francisco–Oakland Bay Bridge. The Oakland segment was extended south to Fremont Boulevard at Beard Road on November 14, 1957, and the gap was filled on November 24, 1958, soon after the state legislature named the highway after Fleet Admiral Chester W. Nimitz. (The short spur to Route 5 at Warm Springs (now SR 262) remained in the state highway system as a branch of Route 69.) As these sections opened, Sign Route 17 (and Legislative Route 69) was moved from its old surface routing, which mostly became local streets. Other than Route 5 south of Warm Springs, the portion from San Leandro into Oakland was also kept as part of Route 105 (now SR 185).