Crestline is a census-designated place in the San Bernardino Mountains of San Bernardino County, California, USA. The population was 10,770 at the 2010 census, up from 10,218 at the 2000 census.GeographyCrestline is located at.According to the United States Census Bureau, Crestline has a total area of 14.0sqmi. 13.8sqmi of it is land and 0.1sqmi of it (1.00%) is water.Crestline is located within the San Bernardino National Forest; Lake Gregory is located in the center of Crestline.ClimateAccording to the Köppen Climate Classification system, Crestline has a warm-summer Mediterranean climate, abbreviated Csb on climate maps.Demographics2010The 2010 United States Census reported that Crestline had a population of 10,770. The population density was 770.4 people per square mile (297.5/km²). The racial makeup of Crestline was 9,289 (86.2%) White (77.0% Non-Hispanic White), 107 (1.0%) African American, 135 (1.3%) Native American, 96 (0.9%) Asian, 20 (0.2%) Pacific Islander, 526 (4.9%) from other races, and 597 (5.5%) from two or more races. Hispanic or Latino of any race were 1,775 persons (16.5%).