Orinda is a city in Contra Costa County, California, United States. The population was 17,643 at the 2010 census, and was estimated in 2019 to have increased to 19,926. In 2012, Forbes ranked Orinda the second-friendliest town in America. The city is just east of Berkeley and is home to many affluent suburban professionals who commute to larger cities in the Bay Area such as Oakland, and San Francisco. Its location provides a more rustic landscape, and its many parks and trails make it a destination for Bay Area hikers and naturalists.
Orinda is located within four Mexican land grants: Rancho Laguna de los Palos Colorados, Rancho Acalanes, Rancho El Sobrante and Rancho Boca de la Cañada del Pinole. The area was originally rural, mainly known for ranching and summer cabins. The Moraga Adobe was built in 1841, and is the oldest building in the East Bay. In the late 19th century, the land was named by Alice Marsh Cameron, probably in honor of the poet Katherine Philips, who was also known as the "Matchless Orinda".
In the 1880s, United States Surveyor General for California Theodore Wagner built an estate he named Orinda Park. The Orinda Park post office opened in 1888.