I would guess at the York county fairgrounds. Beachey was a first class showman. He would ship his "Rubber cow" to various cities and fly around to create a big stir. Here is an example:
_________
Sensing the value of newspaper headlines to his exhibition business, Beachey hit upon a simple but natural idea to stir the imagination of the public and to create newspaper headlines across the nation. He shipped his dirigible to Washington and flew it around the Washington Monument, then down the Mall to the White House where he landed on the grounds and marched in to see President Theodore "Teddy" Roosevelt. The President was not there but Mrs. Roosevelt greeted him on this historic occasion in June 1906. After the Washington sensation, he was booked for appearances throughout the country.
__________
One more note - He was also very concerned with aviation safety. He is credited with discovering how to recover and airplane from a deadly tailspin by turning hard WITH the spin and leveling out the aircraft.
Ironically, he died in a 1915 plane crash while attempting a low level inverted stunt.
I agree, pretty sure it is the York Fairgrounds. I have seen other pics of the fairgrounds, might have some around, I'll have to see if I can find them.