Todd Heisler, A rebuilt version of Fort Union, near the confluence of the Missouri and Yellowstone Rivers in northwestern North Dakota, was was of the sites of the 1837 smallpox outbreak among the Mandan. (TODD HEISLER/ROCKY MOUNTAIN NEWS) (05/18/2005), [432071454] . Denver Public Library Digital Collections, accessed 17/02/2026, https://digital.denverlibrary.org/nodes/view/709476



