Grand Terrace is a city in San Bernardino County, California, United States. The population was 12,040 at the 2010 census, up from 11,626 at the 2000 census. Grand Terrace is located between Highgrove and Colton, along the I-215 and Agua Mansa industrial corridors. The city is located between two mountain ridges: Blue Mountain to the east and the La Loma Hills to the west.