The entrance to the John Glenn Astronomy Park is about 0.9 miles to the West of the Old Man's Cave Visitor's Center along route 664.   Most visitors will take route 33 to Logan Ohio and exit on Route 664.  The Hocking Hills State Park is 11 winding miles down this road. 

Visitors who are coming from the southwest along route 664 will find the JGAP 3.8 miles from South Bloomingville.

Our mailing address is: 

20294 S.R. 664, Logan, Oh, 43138

However this address, when placed in map apps or sites, such as, doesn't  take you to the proper location.  With your GPS unit or app, use the following address:

20531 OH-664, Logan, OH 43138

GPS devices will also bring you to the entrance with the following coordinates:

39 deg 26' N, 82 deg 33.2' W

Or, in decimal:

39.433226, -82.55412