Fort Union Trading Post, Williston, ND ID: 4978 | This file appears in: Fort Union Trading Post Aerial view of Fort Union bastion, fenced walls, and Bourgeois House in background. | Creator: National Park Service photo | Date: ca. 2019 | Source: National Park Service | Rights: Public domain Download Original File CreatorNational Park Service photoSourceNational Park ServiceDateca. 2019RightsPublic domain "Fort Union Trading Post, Williston, ND" appears in: Fort Union Trading Post