Jamestown, CA has a population of 2,621 and is the 9,553rd largest city in the United States. The population density is 873 per sq mi which is 276% higher than the California average and 864% higher than the national average. The median age in Jamestown is 51 which is approximately 41% higher than the California average of 36. In Jamestown, 57% of the population over 15 years of age are married, 97% speak English and 3% speak Spanish. 79% of Jamestown residents were born in California, 16% were born out of state, 0% were born outside of the United States and 5% were foreign born.