Assiniboine River, Manitoba, Canada (Google Maps ⧉, OpenStreetMap ⧉)
Referenced In
History of the Expedition Under the Command of Captains Lewis and Clark: To the Sources of the Missouri, Thence Across the Rocky Mountains and Down the River Columbia to the Pacific Ocean
by Meriwether Lewis, William Clark"Serjeant Pryor, with two others, will then take the horses by land to the Mandans. From that nation he is to go to the British posts on the Assiniboin with a letter to Mr. Henry."