Cartago, CA has a population of 25 and is the 28,696th largest city in the United States. The population density is 21 per sq mi which is 91% lower than the California average and 76% lower than the national average. The median age in Cartago is 80 which is approximately 123% higher than the California average of 36. In Cartago, 76% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 68% of Cartago residents were born in California, 32% were born out of state, 0% were born outside of the United States and 0% were foreign born.