Walnut Creek is a city in Contra Costa County, California, United States, located in the East Bay region of the San Francisco Bay Area, about 16 miles east of the city of Oakland. Walnut Creek has a total population of 70,127 per the 2020 census, is located at the junction of the highways from Sacramento and San Jose (I-680) and San Francisco/Oakland (SR-24), and is accessible by BART. The city shares its borders with Clayton, Lafayette, Alamo, Pleasant Hill, and Concord.

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.