Society of the Army of the Potomac

https://www.nps.gov/long/blogs/images/Medal_1.jpg

The Society of the Army of the Potomac a military society founded in 1869 which was composed of officers and enlisted men who served with the Army of the Potomac during the American Civil War to commemorate the service and sacrifice of those who had served the Union cause during the war.

This society did not transition to hereditary membership when its members died off. It’s last formal meeting was in 1927.