High Quality Content by WIKIPEDIA articles! Highland is a city in San Bernardino County, California, United States. The population in 2010 (US Census) was 53,104, up from 44,605 at the 2000 census. The term Highland also refers to a geographical area of the city of San Bernardino (generally north of Highland Avenue and east of Del Rosa Avenue to the eastern city limits), and parts of unincorporated San Bernardino County.