Atascadero, CA has a population of 29,516 and is the 1,452nd largest city in the United States. The population density is 1,132 per sq mi which is 387% higher than the California average and 1149% higher than the national average. The median age in Atascadero is 39 which is approximately 9% higher than the California average of 36. In Atascadero, 62% of the population over 15 years of age are married, 88% speak English and 9% speak Spanish. 72% of Atascadero residents were born in California, 21% were born out of state, 1% were born outside of the United States and 6% were foreign born.