Here's a list of Tri Delta firsts and accomplishments:
http://www.deltadeltadelta.org/about/acco.htm
My favorite is the fact that we were the first women's fraternity to be FOUNDED as a national organization -- others were national before us, but those were all founded as locals and then eventually decided to expand. Tri Delta had plans to become a national sorority before it even really existed.
Our Alpha chapter at Boston University is still in existence, although it was closed from 1970-1984.