Louis Bradbury made his fortune in gold and silver mining primarily in Mexico, and is famous for the construction of the Bradbury Building, a City of Los Angeles Historical Landmark. Mr. Bradbury also owned a smaller ranch located in the southeastern portion of the City of San Marino. After the passing of Louis Bradbury his heirs lost control of both ranches during the 1930's. Prolonged legal battles between the family members resulted in foreclosure proceedings by the Security National Bank against most of the Bradbury Estate.
The conclusion of World War II brought new growth to what was once the Bradbury Estate and its surrounding area. Large parcels of it were sold to people seeking spacious building sites, which afforded privacy and country living in the foothills of the San Gabriel Mountains. The surrounding properties, in the then unincorporated area called Duarte, were subdivided into tracts, which provided modest and affordable living accommodations for returning service men and their families. The entire area began to change rapidly from a sleepy agricultural area to a sprawling suburb of "GI" tract homes. Local development regulations were established and enforced by the County of Los Angeles. County Departments also provided Police and Fire protection.
In 1957, while the City of Duarte was considered for incorporation, the Bradbury Estate Property Owners Association realized that if development continued at the same pace in Bradbury they would loose the ability to control their vision for the future of this special area. These residents valued the unique foothills and were fearful that they would become victims to the bulldozers of tract developers. In an effort to ease their fears and to control their vision for the future the residents of the Bradbury Estates joined with property owners located within the area, surrounded by Woodlyn Lane, Bradbury Hills Road, Royal Oaks Drive North, Mount Olive Drive and Lemon Avenue, to generate the 500 minimum number of registered voters required to create a new unincorporated City. The incorporation drive was successful and upon approval of the Los Angeles County Board of Supervisors, the City of Bradbury became a municipal corporation on July 26, 1957.