Yes ... the stadium itself is the 4th largest city. State College Borough itself has around 40k residents and there's obviously overlap between those residents and those sitting in the stadium. I've heard estimates that there are 15k people that show up just to tailgate on nice days (that seems high to me). In any case, it's an interesting statistic.

Note that Allentown is relatively safe from State College ever passing it as the Borough itself is small and mostly developed. There are 5 surrounding townships that actually contain most of the area's population.