The IOOF is a fraternal order and mutual benefit society founded in the early 19th century. It is one of the oldest and largest fraternal organizations in the world, emphasizing community service, charity, and personal development. The Grand Encampment is a branch of the IOOF, and the Department Council likely refers to a regional or state-level governing body. The medal commemorates the 66th annual session, indicating a long history of the organization in Pottstown, Pennsylvania.