In 1959, Allegheny alumnus Ossian E. Carr offered a large monetary gift to Allegheny College allowing plans for the construction of a new science building to go forward. Construction on Carr Hall began in spring 1963 and by the fall of 1964, the new structure was opened. The modern-style brick and concrete building more than doubled the available space for the sciences on campus. Many of the clasrooms and laboratories were named for individuals and corporations who made donations to the College. The highlight of the building was the planetarium donated by Lewis "Bud" Wibel '42. In 1995, Carr Hall underwent a $3.5 million renovation.
Ossian E. Carr was alumnus of both the Allegheny Preparatory School and Allegheny College. In 1900, he graduated from Allegheny with a Bachelor of Science degree in engineering. His pioneering work in engineering led him all over the country. In 1955, he was awarded an honorary LLD from Allegheny. The new science building was named in his honor.