Los Angeles County, officially the County of Los Angeles, in the Los Angeles metropolitan area of California, is the most populous county in the United States, with more than ten million inhabitants as of 2018. The county's most visited park is Griffith Park, owned by the city of Los Angeles. The county is also known for the annual Rose Parade in Pasadena, the annual Los Angeles County Fair in Pomona, the Los Angeles County Museum of Art, the Los Angeles Zoo, the Natural History Museum of Los Angeles County, the La Brea Tar Pits, the Arboretum of Los Angeles, and two horse racetracks and two car racetracks (Pomona Raceway and Irwindale Speedway), also the RMS Queen Mary located in Long Beach, and the Long Beach Grand Prix, and miles of beaches—from Zuma to Cabrillo.

Riverside County is a county located in the southern portion of California. The resort cities of Palm Springs, Palm Desert, Indian Wells, La Quinta, Rancho Mirage, and Desert Hot Springs are all located in the Coachella Valley region of central Riverside County. There is a diversity of flora and fauna within Riverside County.

There are 19 official wilderness areas in Riverside County that are part of the National Wilderness Preservation System. Some are part of the protected areas such as Cleveland National Forest, Joshua Tree National Park, San Bernardino National Forest, Sand to Snow National Monument, and the Santa Rosa and San Jacinto Mountains National Monument.

San Bernardino County is located within the Inland Empire area. There are at least 35 official wilderness areas in the county that are part of the National Wilderness Preservation System. A few are the Mojave National Preserve, Dessert Black Mountain Wilderness, Joshua Tree Wilderness, and Golden Valley Wilderness.

The mountains are home to the San Bernardino National Forest, and include the communities of Crestline, Lake Arrowhead, Running Springs, Big Bear City, Forest Falls, and Big Bear Lake.