Point of Observation No. 51

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Lewis and Clark Celestial Observations
at Fort Mandan

Point of Observation No. 51 (1804)
2 November 1804 - 17 April 1805

During the final weeks of October 1804, the Lewis and Clark Expedition awoke to temperatures near or below the freezing point. Blustery northern winds brought icy rain and snow. V-formations of honking geese filled the skies daily, winging their way south to escape the rigors of the northern winter. Meanwhile, contrary to the flow of the river and the advance of the cold, the Expedition pushed northward. On 27 October, after having traveled more than 1200 river miles from the mouth of Kansas River by their estimate, the Corps arrived at the Mandan-Minnitari villages near the mouth of Knife River (near present-day Stanton, North Dakota). William Clark spent part of the next few days seeking a suitable site for the Expedition's winter quarters. He chose a location a few miles downstream from the villages but on the east side of the Missouri. By 2 November 1804, with construction just getting underway,the captains named the encampment Fort Mandan in honor of their Mandan neighbors.


1. Maps numbers are those given in Moulton, Journals, Vol. 1.

2. The meridian identified passes through the Mandan village.

3. St. Louis is at about 90°10' west, thus the Evans map would place the Mandan village at about 107°43' W.

4. This line is shown several miles south of the Mandan village.

5. That is, 11° East.

6. From Thompson's celestial observations.

7. These coordinates for the Mandan village are approximate and likely are from David Thompson's celestial observations.

8. The coordinates of this encampment were determined by "best-fit"-matching the Expedition's latitudes and river survey to a detailed map by G.K. Warren (1856), a map by the Missouri River Commission (1895), "modern" maps and aerial photographs and descriptions of the site by early travelers.