The San Gabriel Mountains, which frame the Los Angeles skyline and lock in the Los Angeles Basin to the north, provide the most forest land, wilderness area and open space in the Greater Los Angeles region. Since the 1800s, the federal government has managed the area as a reserve, forest and national monument. While most federally-managed lands are not located near a city, the San Gabriels are uniquely situated in close proximity to more than 15 million people. This fact has undeniably influenced the evolution of their management and the federal government's approach. This thesis analyzes the dialogue surrounding the management of the public lands in the San Gabriel Mountains and places it within broader dialogues that have taken place nationwide. Chapter One focuses on this dialogue during the Conservation Era, when the management of the mountains was in its infancy, and Chapter Two focuses on contemporary times and uses President Obama's 2014 national monument designation as a reference point. The thesis concludes that, over time, the management of this region has been crucial in the larger picture of forestry, conservation and environmental politics.