Lake Nacimiento, CA has a population of 2,871 and is the 9,033rd largest city in the United States. The population density is 277 per sq mi which is 19% higher than the California average and 206% higher than the national average. The median age in Lake Nacimiento is 46 which is approximately 28% higher than the California average of 36. In Lake Nacimiento, 69% of the population over 15 years of age are married, 93% speak English and 4% speak Spanish. 68% of Lake Nacimiento residents were born in California, 28% were born out of state, 2% were born outside of the United States and 2% were foreign born.