Larkspur is located in Marin county California with a geographic area of 3.0 square miles. The total population in Larkspur is 12,363 with 44.0% male and 56.0% female. Children under age 5 represent 5.7% of the population, under age 18 equal 19.7% of the population and over age 65 is 24.8% of the population. The median household income is $115,543, per capita income is $82,404. There are a total of 5,838 housing units with 48.5% owner occupied. Education includes 5.4% of residents that are high school graduates and 73.4% with a bachelor's degree or higher. The average temperature in Larkspur in the summer is 68 degrees, and in the winter 43 degrees.