Mentone is a census-designated place in San Bernardino County, California, United States. The population was 8,720 at the 2010 census, up from 7,803 at the 2000 census. It is located at 34°3′53″N 117°7′13″W / 34.06472°N 117.12028°W / 34.06472; -117.12028.According to the United States Census Bureau, it has a total area of 6.2 square miles; 6.2 square miles of it is land and 0.19% is water. State Route 38 serves as its main street, called Mentone Boulevard as one enters Mentone from Redlands, then Mill Creek Road as one leaves the district and heads north toward Angelus Oaks and Big Bear.