Old Sem is Cornell College’s first building, with construction beginning in 1852, a year before the College’s founding. Back then, the college was known as the Iowa Conference Seminary and the building was known as the “seminary building.” The construction of Old Sem was an arduous one as the wooden timbers used for the floors and support beams had to be transported via the Mississippi River, then dragged to the building site by oxen-drawn carts. However, the community of Mount Vernon was determined to bring the seminary into existence, and it is they who helped finance and build Old Sem. Once completed, the building was 72 feet long by 40 feet wide and three stories tall.
When classes began on September 5, 1853, the Seminary building was not complete, so classes met in the Methodist Episcopal Church, now the site of the First Street Community Center.The building was officially dedicated in a ceremony on November 14, 1853. Faculty and 161 students (57 women and 104 men), along with townspeople, marched from the Church in downtown Mount Vernon to the college's new home on the Hilltop. They crowded into the first-floor chapel of the newly finished building to hear the benediction that dedicated this “Large and Commodious building.” Despite the lack of indoor plumbing and wood fire heating, it was a promising start to the college.
In 1855, just two years after the completion of Old Sem, the Board of Trustees ruled that the rooms would be occupied by three students instead of two. A mansard roof was added in 1891 to provide another story for the building, although some, like Alice Fellows Rigby, a student during the early days of Cornell, said, “We never liked the mansard roof – it never harmonized with the rest of the building.” In 1869, a new two-story wing was added to the back of Old Sem. This “ell,” a 30 x 20 addition that creates an “L”-shape to the building, was built to provide a kitchen and dining room space, and was given a second floor in the early 1900s. It was the first major renovation to Old Sem and was home to the school’s kitchen and dining room and storage. In 1899, the first floor had been converted into a history lecture room, which it would remain until it became part of the chemistry department sometime prior to 1931.
The usage of the Seminary building began to change after the establishment of College Hall in 1857. Male students ceased to board there and the building began to be used as a women’s dormitory, and referred to as the Ladies Boarding Hall. By 1862 it also held the primary school and music departments. After the completion of Bowman-Carter Hall, the building then became Science Hall, although some students still called it “Old Sem.” In 1891, Cornell’s library was moved out of King Chapel and onto the second floor of Old Sem, where it would remain until the completion of the Carnegie Library in 1905. Between 1885 and 1959, it was home to the chemistry, physics and biology departments. Old Sem also housed art studios on the fourth floor from the mansard roof construction in 1891 until the fire in 1924.
In the 1950s, a gift from the Cowles Foundation allowed the college to remodel Science Hall (Old Sem) into a building for administrative use. The first floor became home to the offices for business, admissions, and the registrar (admissions has since moved, and now residence life is on the first floor), the second floor is home to the offices of the president and deans of the college and the development office, and the third floor became home to the office of public relations, the faculty lounge and conference room, and the service center (the third floor has since been rearranged to include the chaplain’s office and the business services office). After the 1959 renovation, the building was re-christened “Old Sem,” with “old” referring to the building’s venerable history.