Larkspur is a city in Marin County, California, United States. Larkspur is located 3 miles (4.8 km) south of San Rafael, at an elevation of 43 feet (13 m). As of 2006, the city's estimated population was 11,746. Larkspur is located north of San Francisco near Mount Tamalpais. Larkspur's Police Department is shared with that of the neighboring Corte Madera. Adjacent to Larkspur's downtown is Madrone Canyon, which is a residential area and a redwood grove. Janis Joplin's last known residence was located in Larkspur at 380 West Baltimore Drive. Ki Longfellow grew up in Larkspur's Madrone Canyon.