Larkspur, CA has a population of 12,268 and is the 3,357th largest city in the United States. The population density is 4,052 per sq mi which is 1643% higher than the California average and 4372% higher than the national average. The median age in Larkspur is 50 which is approximately 38% higher than the California average of 36. In Larkspur, 57% of the population over 15 years of age are married, 83% speak English and 7% speak Spanish. 46% of Larkspur residents were born in California, 34% were born out of state, 2% were born outside of the United States and 18% were foreign born.