Which was the first campus building to be named after someone who was not a Jesuit?

That would be Dahlgren Chapel, the ninth building on campus, dedicated in 1893. Elizabeth Drexel and John Vinton Dahlgren (A.B. 1889, LL.B. 1891) had originally proposed that a small mortuary chapel be built as a memorial to their infant son, Joseph Drexel Dahlgren, who died in 1891. However, then Georgetown President J. Havens Richards, S.J. had a grander vision, suggesting a larger chapel capable of serving the whole university community which the Dahlgrens agreed to fund. In addition to being the first building named after a non-Jesuit, the Chapel was also the first to be funded exclusively by outside gifts.