Elk Grove is a city in Sacramento County, California, located just south of the state capital of Sacramento. It is part of the Sacramento–Arden-Arcade–Roseville Metropolitan Statistical Area. As of 2015, the population of the city was estimated at 167,965. The second-largest city in Sacramento County, Elk Grove was the fastest growing city in the U.S. between July 1, 2004, and July 1, 2005.