Hidden Valley Lake, CA has a population of 5,618 and is the 5,996th largest city in the United States. The population density is 576 per sq mi which is 148% higher than the California average and 536% higher than the national average. The median age in Hidden Valley Lake is 43 which is approximately 21% higher than the California average of 36. In Hidden Valley Lake, 69% of the population over 15 years of age are married, 89% speak English and 10% speak Spanish. 67% of Hidden Valley Lake residents were born in California, 24% were born out of state, 1% were born outside of the United States and 8% were foreign born.