There are 44 US Post Offices in Kern County serving a total of 779,163 residents equating to 17,708 residents per post office. It's estimated that approximately 1,243,631 packages are handled across the 44 county post offices annually. Kern County is a county located in the U.S. state of California. As of the 2010 census, the population was 839,631. Its county seat is Bakersfield. Kern County comprises the Bakersfield, CA Metropolitan Statistical Area. The county spans the southern end of the Central Valley. Covering 8,161.42 square miles (21,138.0 km2), it ranges west to the southern slope of the Coast Ranges, and east beyond the southern slope of the eastern Sierra Nevada into the Mojave Desert, at the city of Ridgecrest. Its northernmost city is Delano and its southern reach expands just beyond Lebec to the Grapevine and the northern tip of the parallel Antelope Valley. The county's economy is heavily linked to agriculture and to petroleum extraction. There is also a strong aviation, space, and military presence, such as Edwards Air Force Base, the China Lake Naval Air Weapons Station, and the Mojave Air and Space Port. It is one of the fastest growing areas in the United States in terms of population growth, and suffers from significant water supply issues and poor air quality."