San Carlos, AZ has a population of 4,440 and is the 6,976th largest city in the United States. The population density is 518 per sq mi which is 800% higher than the Arizona average and 471% higher than the national average. The median age in San Carlos is 26 which is approximately 30% lower than the Arizona average of 37. In San Carlos, 38% of the population over 15 years of age are married, 60% speak English and 1% speak Spanish. 92% of San Carlos residents were born in Arizona, 5% were born out of state, 0% were born outside of the United States and 3% were foreign born.