Lucas Valley-Marinwood, CA has a population of 6,594 and is the 5,399th largest city in the United States. The population density is 1,151 per sq mi which is 349% higher than the California average and 1170% higher than the national average. The median age in Lucas Valley-Marinwood is 49 which is approximately 35% higher than the California average of 36. In Lucas Valley-Marinwood, 64% of the population over 15 years of age are married, 85% speak English and 5% speak Spanish. 43% of Lucas Valley-Marinwood residents were born in California, 38% were born out of state, 4% were born outside of the United States and 16% were foreign born.