The early 20th century was a time of great change for the Hospital. Between the years 1893 and 1912 the hospital was completely rebuilt following the newly developed cottage plan design. The cottage plan grew in popularity at the turn of the 20th century. The basic idea of the plan was to have multiple smaller buildings which would house only one type of patient each, rather then having all patients in one large building. The buildings would be connected together by long, partially submerged tunnels. The tunnels allowed for patient and employee movement between buildings during the winter months, they also contained utilities like steam and electric for the buildings. During the warmer months patients would walk on walkways which were built on top of the tunnels.

The new buildings were built using the following "cardinal rules". "The buildings will not exceed two stories in height. Two stairways will lead from the second stories, for easy escape in case of fire. The buildings are to be fire-proof; and will be so constructed that they can be warmed at all times to a temperature of 70 degrees. They will be constructed to permit the conditions of domestic life. There will be diversity, and no operative department will be in the basements. Ample cubic space will be provided for ventilation and without materially increasing the cost of maintenance or sacrificing the essential appliances for proper treatment and custody of the classes."

The new hospital was designed by Pennsylvania architects Addison Hutton and John Dempwolf. Henry Orth was the superintendent during the time of the rebuilding. He worked closely with the architects to make sure the new buildings were constructed properly and with patient interests in mind. He determined that there should be one-half acre of ground for each patient, as a result 210 acres had to be purchased in addition to the 292 acres the hospital already owned in 1893. The new hospital was designed to support 1,000 patients. The buildings on the male and female sides of the campus mirrored each other and the campus was meant to represent an Italianate window. Even the floor plan of the Sun Parlor and the main door of the Administration Building echoed the Italianate window design. To the north side of the campus were the male buildings, four in total, including the male nurse home. On the south side were the female buildings, also totaling four including the female nurse home. The North and South Branch buildings that were built during the time of the Main Building would remain in use amongst the new structures well into the twentieth century. At the center of the campus were three communal buildings where both female and male patients were allowed to congregate together. These buildings were the chapel, kitchen, and solarium.  The Infirmary Building at the rear of the campus housed both male and female patients, but they were separated in different sides of the building with a dinning room in the center. At the very front of the campus sat the new Administration Building. There were also numerous support buildings, a morgue was built in the valley to the south of the main campus near the Water Works. A farm located to the rear of the main campus supplied the hospital with all the food it needed and a power plant provided heat and electricity. When all the new buildings were completed in 1912 the hospital resembled a small city.
	An aerial image of the new hospital from 1930
	The main entrance to the Administration Building