According to the USGS, Granite Hills is located at 32°48′11″N 116°54′17″W / 32.80306°N 116.90472°W / 32.80306; -116.90472 (32.8031070, -116.9047476),[3] which is near intersection of Madison Avenue and Greenfield Drive.

The part of Granite Hills within the city of El Cajon consists of a "gerrymandered" corridor, approximately 0.25 miles (0.40 km) wide on the south side of Madison Avenue, roughly through the center of the neighborhood.

According to the United States Census Bureau, the Granite Hills CDP is located at 32°48′15″N 116°54′38″W / 32.80417°N 116.91056°W / 32.80417; -116.91056 (32.804101, -116.910522).

[3] This is approximately 0.4 miles (0.64 km) west-northwest of where the USGS places Granite Hills.

The CDP comprises most of unincorporated El Cajon east of the San Bernardino Meridian, north of Dehesa Road and has a total area of 2.8 square miles (7.3 km2), all land.

Mail sent to all parts of Granite Hills is addressed to El Cajon, California.

There were 1,090 housing units at an average density of 382.6 per square mile (147.7/km2), of which 914 (88.6%) were owner-occupied, and 118 (11.4%) were occupied by renters.

In 2006, El Cajon attempted to annex a small portion of unincorporated land that is part of the Granite Hills CDP (census block 3006) to allow The Home Depot to build a store there.

Protests from the residents of the El Cajon neighborhood surrounding the unincorporated land fell on deaf ears and the annexation was approved by the city council, only to be rejected by the San Diego Local Agency Formation Commission.