Arcata, CA has a population of 17,775 and is the 2,437th largest city in the United States. The population density is 1,955 per sq mi which is 741% higher than the California average and 2058% higher than the national average. The median age in Arcata is 25 which is approximately 31% lower than the California average of 36. In Arcata, 26% of the population over 15 years of age are married, 85% speak English and 10% speak Spanish. 71% of Arcata residents were born in California, 24% were born out of state, 2% were born outside of the United States and 4% were foreign born.