Cedar Grove Sanitarium, introduced in Silent Hill: Origins and located in Central Silent Hill, is a mental health institution for the mentally unstable. Both dates of the founding and construction are unknown, but this psychiatric hospital is active in the 20th century. The establishment is a mixed-gender facility, though the male and female populations are housed separately.
While Alchemilla Hospital is a hospital intended more for physical medicine and operations, Cedar Grove and Brookhaven Hospital are intended more for mental health. However, Cedar Grove still seems to treat physical illness, but mainly contagious diseases.
Cedar Grove is a sprawling facility located on the extreme eastern edge of southern Central Silent Hill, occupying a large lot at the intersection of Acadia Road and Midway Avenue. A tall brick wall surrounds the lot, with only a single (known) portcullis and gate, which has the words Cedar Grove Sanitarium positioned above it, as its main point of entry. A single concrete drive snakes uphill, terminating in a large lot positioned before the main entrance to the sanitarium.
Consisting of two floors and a basement, the sanitarium's first floor appears to be meant for those patients who are mentally ill. The first floor's west wing is where the male population is housed, while the east wing houses the female population. Each wing has a sick ward, a pair of non-specialized wards, dorms, an infirmary and a section designated as either Male or Female Seclusion. A pair of solarium (or sun rooms), a dining hall, cloak room, day room and a room for patient belongings can also be found. Like all structures encountered in Silent Hill, most of the locks have seized or the doors have jammed, or they've simply become blocked.
The second floor appears to be where those who are contagiously ill are kept. Many of the rooms are used to care for either specific diseases, such as tuberculosis or polio, or are used as a means to keep contagious patients separate from the general population, depending on the severity of the contagion. As with the first floor, the second floor is divided in half, with the west wing housing the male population, while the east wing houses the female population.
The basement is used primarily as storage space. Rooms are spread across the basement and are connected by a series of long corridors. In addition to storage, rooms designed to allow maintenance on the building's piping rest on both the east and west sides of the basement, while access to the boilers is made possible through the boiler room to the south.
Silent Hill: Origins
After his struggle through the Otherworld iteration of Alchemilla Hospital, Travis Grady makes his way through the streets of Silent Hill to the Cedar Grove Sanitarium. There isn't really a clear-but motive as to why Travis needs to explore the asylum; Lisa Garland said Michael Kaufmann wanted to meet her there, but there's no reason for Travis to pursue either. It could be presumed that Travis is searching for people in the seemingly deserted town.
The interior of the building is unlit, and the flashlight affords little illumination. Inside the West Solarium, Travis can pick up his first firearm, the Target Pistol. The main doors leading to the east wing are not functional, so Travis is forced to detour through the East Solarium. As he exits the East Solarium, he has his first personal encounter with Dahlia Gillespie, the mother of Alessa Gillespie, who Travis had saved from a fire and who is instrumental in his travel between worlds. The woman warns Travis not to trust her daughter, as she knows not what she does. Using her behavior as the standard, Travis comes to the conclusion that most, if not all, of Silent Hill's residents must be crazy.
As he continues his journey through the institution, Travis finds quite a few medical reports related to a female patient, who is revealed to actually be Travis's mother, Helen Grady. She was committed to Cedar Grove just after attempting to kill herself and Travis by natural gas inhalation. She was doing this because "the people in the mirrors" were telling her that her son was a demon. This suggests she may have had prior experiences with the Otherworld phenomenon.
Like Alchemilla Hospital, the ultimate goal is to obtain a piece of the Flauros. After using the Jocasta Artifact, Travis finds Lisa alone in a room sitting on a chair with Michael Kaufmann nowhere in sight. Lisa sadly talks about a woman who always waits for her son and when Travis asks who it is, Lisa replies sternly "You KNOW who's in there!", before running off.
Travis reaches his mother's cell and finds her Otherworld counterpart called "Momma" trapped in a large gibbet cage. After defeating her he finds another triangular piece, which is named Past Piece, and Alessa appears as Travis passes out again. Upon waking, Travis finds a theater ticket on a table near main entrance and insinuates that he should check out Artaud Theater.