Except for the notorious roadhouses in Sycamore Grove, Highland Park might never have have become annexed to Los Angeles.
Hard liquor flowed freely in the saloons and roadhouses, which served as stopovers for the red-light district in nearby Garvanza. The Arroyo in general was a favorite location for bandits who preyed on travelers. It was the inability of Highland Park residents to control the behavior of those loitering in the Arroyo that drove them to seek incorporation with the City of Los Angeles and its police force. Highland Park joined Los Angeles in 1898.
In 1905, seven years after Highland Park's annexation to the city, a section of the Sycamore Grove Park was purchased by Los Angeles, for its recreation system, and two years later the remainder of the present 15 acre site was donated by E. R. Brainerd.
Sycamore Grove Park is located on one edge of the old Rancho San Rafael, a grant of private land, made to Jose Verdugo in 1784 by Pedro Fages, the military governor of Spanish California.