Boland Hall, the main building on Prep's campus, is home to administrative offices, including those of the President and Headmaster as well as the Office of Campus Ministry.
The building was funded by alumnus Henry Walters, class of 1869, and was completed in 1918. Due to World War I, the building was used to house female government employees until 1919, when the first students began attending school in the building. It was formerly known as the Main Building, until its official dedication as Louis J. Boland Hall in 1988.
Also located in Boland Hall is the health center and the South Room, the main dining area for students on campus. The South Room serves breakfast and dinner to residents daily, and serves lunch to all students, faculty and staff on school days. Sophomore, junior, and senior boarding students reside on the upper floors of Boland Hall.