[1] It commonly includes El Cajon, La Mesa, Lemon Grove, Poway, and Santee, as well as suburban and rural unincorporated communities such as Lakeside, Spring Valley, Jamul, and Alpine.

Many sources also include vast swaths of the backcountry of San Diego County also known as the Mountain Empire, including communities along Interstate 8 such as Pine Valley and Descanso, and communities along the rural section of California State Route 94 such as Potrero, Boulevard, and Jacumba.

[2] Other sources consider communities within the entire eastern two-thirds of the county to be East County, thereby encompassing places like Ramona, Julian, and Borrego Springs,[3][4] The Ramona area—Ramona, San Diego Country Estates and Barona Mesa—is often considered part of inland North County due to its association with Rancho Bernardo, Escondido and other North County Inland communities.

A broader definition of East County exists that includes the Cuyamaca Mountains and the Laguna Mountains, as well as the desert area of Anza-Borrego Desert State Park.

Important landmarks in East County included El Capitan, Mt.