The Maryland General Assembly authorized Crownsville on April 11, 1910, explicitly specifying that it not be located in Baltimore. The Board of Managers purchased 500 acres of former farmland for $19,000. The first twelve patients arrived on March 13, 1911, and were housed in a willow curing shed beside a pond. What followed was extraordinary in its cruelty: those patients built the hospital themselves. Men served as hod carriers, pushed barrows of concrete up tramways three and a half stories high, excavated 10,000 cubic yards of earth in ten weeks, and unloaded 238 railcars of building materials. Women knitted and mended clothing for both staff and fellow patients. Construction on the first major building began in October 1912 while disease swept through the grounds. Smallpox, scarlet fever, and tuberculosis struck the unprotected population. By the 1914-1915 reporting period, nearly 30 percent of deaths were from tuberculosis alone.

Conditions at Crownsville were catastrophic by the 1940s. A 1944 confidential report found the hospital 30 percent over capacity, while white-serving institutions were only 11 percent over. The death rate told the clearest story: 102 per 1,000 patients at Crownsville, compared to 59 and 60 at the two large hospitals for white patients. In one inspection, 25 patients in the ward for the intellectually disabled were found completely without clothes. A 1945 letter to the governor reported that a single employee was on duty overnight in a division housing 90 men. The Baltimore Sun published a devastating series in 1948-1949 under the headline "Maryland's Shame." By then, Crownsville held about 1,800 patients. Of those, 103 received shock treatments, 56 received experimental malaria inoculations, and 33 received lobotomies. The patient census peaked at 2,719 in 1955, with just four attendants covering 560 patients in the main building.

Through the 1940s, the NAACP pressed for African American staff at Crownsville but met resistance from the Commissioner of Mental Hygiene. The hospital had been entirely white-staffed until 1948, when Vernon Sparks was hired in the Psychology Department. Direct-care positions remained closed to Black employees until 1952. By 1959, 45 percent of Crownsville's staff was African American, compared to just 6 to 8 percent at other state hospitals. Patient integration came slowly. The superintendent who transferred 15 Black children to the all-white Rosewood State Training School in December 1954 was threatened with reprimand and resigned the following year. Adolescent patients were not integrated until 1962, adults not until 1963. Among those who suffered at Crownsville was Elsie Lacks, the eldest daughter of Henrietta Lacks, whose cells became the famous HeLa line. Elsie was institutionalized for epilepsy and died there in 1955 at the age of 15.

In 1964, Dr. George McKenzie Phillips became Crownsville's first African American superintendent and began transforming the institution. He established day treatment programs, school mental health outreach, and community clinics providing free medication. Training programs drew students from Israel, Ireland, Spain, Germany, Turkey, and Chile. The hospital staff became known for resisting the national trend of dumping patients into shelters and onto streets. Improved psychiatric treatments, stricter admission standards, and better-funded outpatient care steadily reduced the population from its 1955 peak of 2,719 to just 200 by 2000. The hospital finally closed in July 2004, its remaining patients transferred to two other Maryland facilities.

Today the site is the Crownsville Hospital Memorial Park, acquired by Anne Arundel County from the state in December 2022. The original buildings still stand, weathered brick testaments to the labor of the patients who raised them. In a cemetery on the grounds, approximately 1,600 patients lie in graves marked only by numbers, with names added only to the more recent burials. The site was rededicated in 2004, and a master planning effort launched in October 2023 envisions the property as a place that is, in the community's words, "truthful about its past" while focusing on healing, equity, and education. From above, the old campus spreads across its wooded acreage, a quiet place that carries a weight far beyond what its modest buildings suggest.