In 1903, the Sisters of the Good Shepherd arrived in Dubuque, intending to establish themselves in the city long-term. Two years later, they would move into a new building that would eventually become key educational building at Loras College: Hennessy Hall.
Construction of Hennessy Hall completed in 1906 and housed the Sisters for ten years as they served as accommodations for wayward girls. The facility initially included dormitories, school rooms, sewing rooms, a kitchen and laundry and would serve as their home until October 1915, when they sold the building to Loras College (then Dubuque College) due to the proximity of the recently-constructed Loras Hall, now known as Keane Hall.
After taking possession of the building, the College remodeled the interior, and it became Science Hall, the main building for teaching the sciences.
On March 28, 1932, A fire broke out in the Science Hall at 9:15 pm. It was believed to have been caused when a spark from a defective wire caused the combustion of chemicals or fumes. Two rooms on the third floor suffered damage, as well as the attic and roof. It also destroyed “valuable instruments.” Staff living in the hall found and then fought the fire, while Loras Hall students also rushed to help. The firemen used water and 40 gallons of chemicals to extinguish the blaze.
In conjunction with the College’s centennial celebration in 1939, Science Hall was renamed Hennessy Hall in honor of former Archbishop John Hennessy.
In the early 1940s, Hennessy Hall was the location of flight training for the Civil Aeronautics Authority.
After the St. Joseph Hall of Science opened in 1963, Hennessy, which had housed the science department since 1916, was converted to general classroom space. A new permanent health center would also be established there, the first of its kind on campus since 1952, because the original infirmary, Smyth Hall, was converted to a residence facility.
Situated on the west side of campus facing Alta Vista Street, the building has a limestone block foundation with load-bearing brick masonry walls laid in stretcher bond. The three-story building has two additional stories partially underground with a symmetrical front façade and a pedimented porch entrance. The building is a vernacular building with a classical revival porch over its main entrance and an asphalt-shingled hipped roof with five hipped roof dormers, two on the side and one centrally located on the façade. The eaves of the building and dormer have large overhangs.