Da Yooper said:
Grand Army of the Republic=== G.A.R.
It was one of the largest Union veterans associations following the Civil War. There was others (Union Veterans League, Military Order of the Loyal Legion of the United States, etc.). The GAR had thousands of posts across the nation and would have "encampments" read state, regional and national meetings where members wore "lodge pins" that were for the various encampments.
Now normally the medals I have and have seen say "encampment." Which makes me wonder if this could be some other group like the Loyal Order of the Redman...wait...I found it
Apparently the Knights of Maccabees called their gatherings "Great Camps."
http://www.phoenixmasonry.org/masonicmuseum/fraternalism/maccabees.htm
http://users.pullman.com/fjstevens/tokens/tokens/4752.html
I found the reference in an obit to a person being the organizer of teh Great Camp for the Knights of Maccabee
Keep in mind the 1860s-1890s is referred to as the Golden Age of Fraternalism when a series of organizations were created and in many cases they provided a social, beneficial (insurance, assistance, etc.) and community enhancement role. Many still exist, albeit in much smaller numbers.
As to the G.A.R., they gave way to their descendants as the march of time called them to their final muster. However, the Sons of Union Veterans of the Civil War (www.suvcw.org) still exists today. For woman, they have five orders associated with the G.A.R. that they could join but the common is the www.duvcw.org daughters of union veterans of the civil war.
Rod