Seal Beach, CA has a population of 24,510 and is the 1,776th largest city in the United States. The population density is 2,172 per sq mi which is 835% higher than the California average and 2298% higher than the national average. The median age in Seal Beach is 58 which is approximately 60% higher than the California average of 36. In Seal Beach, 62% of the population over 15 years of age are married, 84% speak English and 5% speak Spanish. 50% of Seal Beach residents were born in California, 34% were born out of state, 1% were born outside of the United States and 14% were foreign born.