Arroyo Grande, CA has a population of 17,842 and is the 2,426th largest city in the United States. The population density is 3,005 per sq mi which is 1193% higher than the California average and 3217% higher than the national average. The median age in Arroyo Grande is 46 which is approximately 26% higher than the California average of 36. In Arroyo Grande, 64% of the population over 15 years of age are married, 85% speak English and 8% speak Spanish. 66% of Arroyo Grande residents were born in California, 23% were born out of state, 1% were born outside of the United States and 11% were foreign born.