How do I locate and loosen the rear derailleur hanger bolt?

Question

Context:

I need to remove my rear derailleur so that I can attach an alignment tool and straighten things out.

Images of the rear derailleur while the bike is upside-down:

• http://www.zooomr.com/z/photos/zoom/9626152/size-8/
• http://www.zooomr.com/z/photos/zoom/9626153/size-8/

Question:

Where is the derailleur's hanger's bolt that attaches the derailleur to the frame?

Solution:

1. Find a hex wrench with a long handle (at least as long as the 3-way hex wrench from Park Tools)
2. Turn counter-clockwise in the area circled in red by Jerry.

Answer 1

I've put a red circle around the hanger bolt.

Answer 2

Jerry Coffin has correctly displayed it.

You can also see it in the context of a bare frame. In the pictured Salsa Fargo, with a black removable derailleur hanger at the rear dropouts, you can see the projection that hangs down with a hole in it. That's what the hanger bolt screws into.