Opened in 1915 as the Norwalk State Hospital and later changed to the Metropolitan State Hospital (MSH) was the sixth state hospital to be built and dedicated to mental illness. The original campus encompassed some 300 acres on the border of Norwalk and Santa Fe Springs, then rural villages in Los Angeles County. The hospital campus was designed using the "Green City" urban design and "Cottage Plan" institutional design principles. The implementation of these design principles moved MSH away from the conventional congregate asylums of the period. Between1915-1950 MSH developed using patient labor as a form of therapy. Patients constructed buildings, infrastructure, and landscaped the grounds. The MSH hospital is distinguished by its informal human-scale buildings and expansive greenspaces. These features contribute to the hospital's home-like environment. When originally constructed, the hospital provided a calm and rural environment.  

In 1980, the MSH campus was determined eligible as a National Register of Historic Places and California Register of Historical Resources (NRHP/CRHR) historic district. In 2017, JRP Historical Consulting resurveyed the MSH Historic District and determined it still retained significant integrity. At that time, JRP also concluded that MSH is eligible for California State Historic Landmark designation.

MSH meets NRHP/CRHR criterion A/1 (history) for "the important role it played in the evolution of public institutional mental health care as the first state hospital campus to be organized entirely around the Cottage Plan Model" and C/3 (architecture) "as a relatively intact example of Cottage Plan institutional design, which opened during the peak of the concepts popularity and on which its principles were fully realized."

In 2019 the State of California has proposed the construction of a new California Highway Patrol Santa Fe Springs Area Office Replacement Project that will significantly impact the hospital's integrity.