Lancaster, CA has a population of 159,651 and is the 158th largest city in the United States. The population density is 1,693 per sq mi which is 629% higher than the California average and 1769% higher than the national average. The median age in Lancaster is 32 which is approximately 12% lower than the California average of 36. In Lancaster, 47% of the population over 15 years of age are married, 77% speak English and 19% speak Spanish. 71% of Lancaster residents were born in California, 15% were born out of state, 1% were born outside of the United States and 13% were foreign born.