Clayton is located in west California. Clayton is part of Contra Costa County. Clayton has 3.84 square miles of land area and has no water area. As of 2010-2014, the total Clayton population is 11,328, which has grown 5.26% since 2000. The population growth rate is much lower than the state average rate of 12.39% and is much lower than the national average rate of 11.61%. Clayton median household income is $131,136 in 2010-2014 and has grown by 29.01% since 2000. The income growth rate is about the same as the state average rate of 29.47% and is higher than the national average rate of 27.36%. Clayton median house value is $583,300 in 2010-2014 and has grown by 62.61% since 2000. The house value growth rate is lower than the state average rate of 75.60% and is higher than the national average rate of 46.91%. As a reference, the national Consumer Price Index (CPI) inflation rate for the same period is 26.63%. On average, the public school district that covers Clayton is better than the state average in quality. The Clayton area code is 925.