The main school building, completed in 1852, is an imposing brick edifice rising four stories on one of the highest plots of land in Catonsville, with approximately 330 x 80 square feet on each floor. The historic chapel graces the center of the school on the second and third floors. Many Mount de Sales Academy graduates are married in this chapel, which houses historic stained glass windows from Chartres, France, a beautifully restored crystal chandelier, and an historic, maintained pipe organ. The remainder of the building contains 33 classrooms, labs, art rooms, library, a music hall, and other offices. Recent renovations include the B-side fourth floor, side chapel expansion, and new Science Research Lab. This building is emblematic of how the rich traditions of Mount de Sales Academy continue to shape and inform the academic, spiritual, emotional, and physical growth of our twenty-first century students.