San Diego County's Board of Supervisors District 4 is an urban and suburban district that blends diverse communities, ranging from bustling city neighborhoods to more relaxed suburban locales. The district includes the entirety of the cities of Lemon Grove and La Mesa, along with significant portions of the City of San Diego.

The district starts in the northwest corner of the Clairemont Mesa area in San Diego, known for its family-friendly atmosphere and suburban feel. Moving south, the district encompasses parts of Linda Vista, Mission Valley, Old Town San Diego, and Uptown. These areas combine historical sites, like Old Town, with modern urban living and commercial activity, especially in Mission Valley.

In the heart of the district lies Balboa Park, a cultural and recreational hub in San Diego, known for its museums, gardens, and the world-famous San Diego Zoo. Surrounding neighborhoods, including North Park and City Heights, contribute to the district's vibrant and diverse urban character. North Park, in particular, is noted for its arts scene and craft beer culture.

The district also includes Lemon Grove and La Mesa. Lemon Grove is recognized for its small-town charm within the urban area, and La Mesa offers a mix of suburban living and a quaint downtown area, known as the Village.

The eastern areas of the district, such as Spring Valley and the Casa de Oro-Mount Helix area, add a more suburban and semi-rural quality to the district, contrasting with the urban centers.

In the City of San Diego, the district also includes communities such as Kearny Mesa and Serra Mesa. Kearny Mesa is known for its diverse array of businesses and cultural influences, particularly Asian cuisine and markets, while Serra Mesa offers a suburban environment with a strong sense of community.

District 4's composition reflects a microcosm of San Diego's broader urban landscape, combining dense, culturally rich urban neighborhoods with quieter suburban areas. This mix provides a range of living experiences, from the hustle and bustle of city life to the more laid-back atmosphere of suburban communities. The district's diversity is also mirrored in its demographic makeup, showcasing a wide array of cultural and socio-economic backgrounds, making it a unique and integral part of San Diego County.