I picked this up on Twitter from Mike Burnop:
Sad day in B'burg & VaTech as former president T Marshall Hahn has passed away. Incredible man & what a life & legacy. A dear friend!— Mike Burnop (@MikeBurnopVT) May 30, 2016
This is indeed very sad news for the entire Virginia Tech community. Dr. Hahn oversaw some of the most transformative changes in the history of our beloved VT, as noted by VT News when the Chemistry-Physics building was named in his honor:
Hahn, who was president from 1962-1974, spearheaded some of the most significant changes in the university's history. By fully opening enrollment to women, expanding undergraduate and graduate degree offerings, eliminating the mandatory military requirement, and reorganizing the institution's colleges, Hahn transformed the college then know as Virginia Polytechnic Institute (VPI) into a major academic institution that, today, is Virginia's leading research university.
Hahn came to Virginia Tech in 1954 as a professor and head of the Department of Physics. He left in 1959 to serve as dean of arts and sciences at Kansas State University, but returned three years later to become the university's youngest president, at age 35.
Enrollment nearly tripled during Hahn's tenure, increasing from 6,000 to 17,000 students, which led to the construction of new residence halls and academic buildings and the renovation and enlargement of many other facilities. Lane Stadium, Cowgill Hall, and Slusher Hall are just a few of the prominent buildings added to campus during Hahn's 12 years as president.
Other firsts under Hahn's leadership included the hiring of a black faculty member, the graduation of a black woman, and the opening of the corps of cadets to women.
http://www.vtnews.vt.edu/articles/2009/10/2009-791.html
Update: official announcement from VT: http://vtnews.vt.edu/articles/2016/05/hahnmemoriam.html
You can't go anywhere on campus without seeing some reference to Dr. Hahn and his family. He will always be an immensely important figure in Hokie history.
Condolences to all who knew and cared about him.

Comments
He was during my time at Tech, always a man of integrity and a great leader. May he rest in peace.
He was before my time, but he clearly had a huge, positive impact on Virginia Tech.
RIP
He will be missed ,he i the single largest reason "& State University" is on our school's name.
Dang, university president at 35. That's some serious accomplishment.
AND had his PhD at age 23 (after serving two years in the military). Here I am entering the third year of my graduate program at age 24 like:
Here I am just finishing my first year of grad school at 26 and I'm like ^
He was responsible for the addition of both my majors to the course of study at VT. I owe him a debt of gratitude without ever having met him.
Thank you sir, it would have been rough having to travel to JMU every weekend to party with COEDS, RIP...
I thought that's why they started Radford, so the cadets would have coeds nearby...
Entirely possible, my rat year ('97-98) they told us not to go to Radford as 90% of the coed's had STD's...
I heard the same thing when I was entering college in 2000
that, my friend, is a textbook example of a tragedy of the commons
RIP Dr. Hahn. Your contributions to the university are present every day and into the future. Truly a great visionary.
When he left in '74,
was it for another position somewhere else?Scratch that. Question answered: GPC. I'm curious what prodded him to leave. Feels like a short time.