Rodeo is a census-designated place (CDP) located in Contra Costa County, California, in the East Bay sub-region of the San Francisco Bay Area, on the eastern shore of San Pablo Bay, 25 miles northeast of San Francisco. The population was 9,653 at the 2020 census. The town is named for the rodeos common in the late 19th century. Cattle from the surrounding hills were regularly driven down through the old town to a loading dock on the shoreline of San Pablo Bay for shipment to slaughterhouses, a practice which continued through the early 20th century. The town of Rodeo is served by the Interstate 80 freeway and State Route 4. The Southern Pacific Railroad main line passes through Rodeo. Rodeo has not been a stop on the railroad since the 1950s.

Contra Costa County is a county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States Census, the population was 1,165,927. The county seat is Martinez. It occupies the northern portion of the East Bay region of the San Francisco Bay Area and is primarily suburban. The county's name refers to its position on the other side of the bay from San Francisco. Contra Costa County is included in the San Francisco–Oakland–Berkeley, CA Metropolitan Statistical Area.