Jefferson Park's boundaries are, roughly, Western Avenue on the east, Adams Boulevard on the north, Crenshaw Boulevard on the west, and Exposition Boulevard/Rodeo Road on the south. It is bordered by Arlington Heights on the north, Mid-City on the northwest, Leimert Park/King Estates on the south, and West Adams on the east. Major east-west roads through the district include Adams, Jefferson, and Exposition Boulevards, and 7th, 10th, and Arlington Avenues which run north-south. The Santa Monica Freeway (I-10) runs just north of the district, parallel to and between Washington and Adams.
With development commencing around the turn of the 20th century, Jefferson Park began as one of the city's wealthiest areas. On the hills rising west of Western Avenue, wealthy white Angelenos built fine Edwardian, Craftsman, and Art Deco mansions, with churches and commercial buildings of commensurate expense. Some wealthy blacks moved into the area as well, leading the neighborhood to be dubbed "Sugar Hill" by many African-Americans of the day. To the south, in the flatter areas along Jefferson Boulevard, a low-rise commercial corridor developed, with small single-story homes and low-rise apartment buildings in the blocks behind. After the 1948 Supreme Court ruling that banned segregationist covenants on property, most of Jefferson Park's white population decamped to other parts of the region, in turn being replaced by upper-middle and upper-class blacks whose descendants still reside in many of the district's spectacular homes.