San Bernardino County is located in Southern California and was the fifth most populous county in California and the twelfth most populous county in the United States according to the 2010 Census. San Bernardino is the county seat. The county is 90 percent desert and receives around 15 inches of rain per year. The San Bernardino Valley and San Bernardino Mountains make up the other 10 percent.
McDonald's and Taco Bell both started in San Bernardino County. Dick and Mac McDonald opened their McDonald's Barbecue Restaurant in 1940. The original restaurant is an unofficial museum on Route 66, as of October 2015. Glen Bell opened Bell's Drive-In in 1946, and Taco Tia in 1948. Bell combined the two restaurants and opened the first Taco Bell in Downey in 1962.
Ozzy Osbourne holds OzzFest in San Bernardino each year. The county also hosts three electronic music Wonderland festivals every year, including the springtime Beyond Wonderland, fall's Nocturnal Wonderland and Escape from Wonderland on Halloween weekend.
San Bernardino County has 35 national wilderness areas in its borders, more than any other county in the United States. The county also contains parts of Joshua Tree National Park and Death Valley National Park. The Mojave National Preserve is located between Interstate 15 and Interstate 40 in the county.