According to the United States Census Bureau, Crestline has a total area of 14.0 square miles (36 km2).

The greater community of Crestline includes the neighborhoods known as Valley of Enchantment, Valley of the Moon, Cedarpines Park, and Twin Peaks.

The racial makeup of Crestline was 9,289 (86.2%) White (77.0% Non-Hispanic White),[6] 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.

According to the 2010 United States Census, Crestline had a median household income of $50,079, with 16.8% of the population living below the federal poverty line.

There were 6,695 housing units at an average density of 616.2 per square mile (237.9/km2).

The racial makeup of the CDP was 88.0% White, 0.8% African American, 1.1% Native American, 0.6% Asian, 0.2% Pacific Islander, 5.0% from other races, and 4.3% from two or more races.

In the California State Legislature, Crestline is in the 19th Senate District, represented by Republican Rosilicie Ochoa Bogh, and in the 34th Assembly District, represented by Republican Tom Lackey.

Almost all of the CDP is served by the Rim of the World Unified School District.

A small portion of the CDP extends into Hesperia Unified School District.