Highly detailed map of the region bewten the Red River and Lake Superior, centered on the course of the Missisippi River above Lake Pipin, the Sioux Villages and the Falls of St. Anthony, which appeared in Henry Schoolcraft and James Allen's Journal of an Expedition into the Indian Country to the Source of the Mississippi in 1832.
The map is a truly remarkable accomplishment. Allen had only a compass which he placed before him in the canoe. With each change in direction of the river he made notes in his field book and by establishing a scale of proportions in the lengths of the reaches, "I was also in this way enabled to lay down and preserve the general curve of a river with surprising accuracy.On the portion of the river above Cass Lake which was the least known of any part of the river and route, I bestowed on tracing and computing of distance the most unremitted attention." Warren notes that "to Lt. Allen we are indebted for the first topographical and hydrographical delineation of the source of the Mississippi and this, somewhat improved by Mr. Nicollet, is our authority at the present time for the Mississippi above the mouth of the Swan River."
The map delineates the region of present day Minnesota from the western tip of Lake Superior to the Red River. It depicts Fort Snelling, scores of Sioux villages, American Fur Company trading posts, and other details. Schoolcraft led the expedition into the upper Mississippi Valley to attempt a reconciliation between the Sioux and the Chippewa, and to vaccinate the Chippewa Indians. He found time to search for the headwaters of the Mississippi which led him to the source in Lake Itaska. Allen talked with the fur traders at every opportunity, obtaining information as to the state and extent of their trade, their relations with the British companies and the amount of business they did.