Riverside County is located in Southern California, to the East of Los Angeles. It is the fourth most populous county in the state, with a combination of dense urban and suburban populations, as well as many rural desert communities. The county is home to a the cities of Riverside, Moreno Valley, and Palm Springs. Riverside County is known for its rich history, with a number of significant cultural and historical sites located within its borders, such as March Air Reserve Base, a large military installation that has played a key role in the region's history. Riverside County is also home to a number of natural attractions, including the Santa Rosa and San Jacinto Mountains National Monument and Joshua Tree National Park. The county is also part of the Inland Empire, a region known for its thriving agricultural industry and diverse economy.