Visitors entering Fort Union from the river side had to pass through outer and inner gates separated by an enclosed area with access to the Indian Trade Room. When the outer gate was closed, trading could be carried on through a wicket, or window, just to the left of the entrance. The configuration of this area provided security during periods of hostilities and when the threat of smallpox was present. It also permitted separating unfriendly Indian groups from each other when they came to Fort Union to trade. A giant fur press was located near the front gate, and this huge device compressed furs into 100 pound bales for shipment to St. Louis.