Alta Sierra, CA has a population of 6,639 and is the 5,371st largest city in the United States. The population density is 798 per sq mi which is 243% higher than the California average and 781% higher than the national average. The median age in Alta Sierra is 52 which is approximately 43% higher than the California average of 36. In Alta Sierra, 69% of the population over 15 years of age are married, 94% speak English and 3% speak Spanish. 69% of Alta Sierra residents were born in California, 25% were born out of state, 0% were born outside of the United States and 5% were foreign born.