Beta Theta Pi's Alpha Chapter is at Miami of Ohio (August 8, 1839), and they are pretty strong there. They have had a rough recent history, but have turned it around in the past few years.
Note: Beta Theta Pi's Gamma Chapter, located at Washington and Jefferson, was established on June 1, 1842 and was the first fraternity established at W&J and in Pennsylvania, and is currently the oldest chapter in continuous existance in the world.