Orinda incorporated as a City in 1985, after more than 100 years of gradual development. As a relatively new city, it has a population of approximately 18,000 residents and a demographic that is shifting from a largely senior base to one that includes younger families. Orinda is situated in the Oakland/Berkeley hills immediately east of the Caldecott Tunnel on Highway 24 in Contra Costa County, California. "Please see bid link for more information" http://www.cityoforinda.org/bids.aspx?bidID=19