There's osage in Pennsylvania I guarantee it. Here near Rochester, NY this is what I did and I suggest you do the same...
-I drove around the country outside of the city on the weekends until I found areas where there were hedgerows (osage was widely used across NY and PA to contain cattle prior to barbed and electric fences so I'm sure it's out there).
-I asked folks working at the local grocery stores who owns most of the farmland in that particular area (ask enough people and you will eventually get a name or names).
-I called the landowners and explained that I make traditional bows and would gladly make one for them or a family member in exchange for permission to cut dead wood off their hedgerows.
-I got a few "no"s, but eventually spoke with a gentleman who was willing to meet me to talk about it.
-He now is a good friend and allows me to cut as much as I please.