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.
Crestline is located at 34°14′33″N 117°17′24″W.
According to the United States Census Bureau, Crestline has a total area of 14.0 square miles (36 km2). 13.8 square miles (36 km2) of it is land and 0.1 square miles (0.26 km2) of it (1.00%) is water.
Crestline is located within the San Bernardino National Forest; Lake Gregory is located in the center of Crestline.
According to the Köppen Climate Classification system, Crestline has a warm-summer Mediterranean climate, abbreviated Csb on climate maps.
At the 2010 census 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%).
The census reported that 10,723 people (99.6% of the population) lived in households, 39 (0.4%) lived in non-institutionalized group quarters, and 8 (0.1%) were institutionalized.
There were 4,360 households, 1,286 (29.5%) had children under the age of 18 living in them, 2,108 (48.3%) were opposite-sex married couples living together, 451 (10.3%) had a female householder with no husband present, 247 (5.7%) had a male householder with no wife present. There were 309 (7.1%) unmarried opposite-sex partnerships, and 57 (1.3%) same-sex married couples or partnerships.