No. 240.

The Secretary of War to the Secretary of State.

Sir: In reply to your letter of the 17th instant, I have the honor to inclose, herewith, copies of the report of Captain D. P. Heap, United States Army, upon the location of the new military post and reservation known as Fort Pembina, Dakota Territory, together with a plot of the reservation.

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Captain Heap to Major General Hancock.

Sir: * * * * * * *

After the completion of the survey of the reservation selected by the hoard General Sykes left me, and I went at once to Pembina, camping near the post set up by Major Long, which post is at present recognized as the boundary line between the United States and the British Possessions. Here, in accordance with verbal instructions received from Major General Hancock, I commenced at once taking observations for latitude, to determine the true position of the forty-ninth parallel. Both Mr. King and myself took a large number of observations, remaining five days at this camp for this purpose. From the whole number I selected six observations which I believed to be the most accurate and reliable, and which most closely agreed with each other. A mean of these six places Long’s post in latitude 48° 59' 13?, or 4,763 feet south of the forty-ninth parallel. The result I believe to be as accurate as could be obtained with the instruments at my disposal. Observations with finer instruments may change the result somewhat.

It so happened that of the six observations selected, three were taken by Mr. King and three by myself.

Having determined the latitude, I planted a large oak post 4,763 feet north of Long’s post, on the edge of the woods on the west bank of the Red River. On this post “U. S.” was chiseled on the south side, “B. P.” on the north side, and “49th °” on top. From this point I ran the parallel thirty-five miles west, nearly to the foot of Pembina Mountain, marking each mile by a stout stake driven through three sods, cut on the direction of the parallel. Each stake has “U. S.” chiseled on its south side, and “B. P.” on its north side.

It may be interesting to know that while running the parallel, I saw drift-wood five miles west of Red River.

The ground from the Red River to the foot of Pembina Mountain has a gradual upward slope of not much more, I should judge, than one foot to the mile.

Having completed this duty, which took me till June 3, I rested one day, and on June 5 started for Fort Wadsworth, via Fort Totten. Mr. Bellon, guide at Fort Totten, was going there at the time, and could be of service to me; and I was also enabled to measure the distance from St. Joseph to Fort Totten and make a map of the country.

I reached Fort Totten on June 8. The distance is about one hundred and eight miles; plenty of water along the route at this season; in dry weather there is scarcely any. No wood from Pembina Mountain to east end of Devil’s Lake; roads generally good.

* * * * * * *

Very respectfully, your obedient servant,

D. P. HEAP, Captain of Engineers.

Assistant Adjutant General, Headquarters Department of Dakota.


Headquarters Department of Dakota, St. Paul, Minnesota, August 3, 1870.

Respectfully forwarded to the Adjutant General of the Army, through headquarters Military Division of the Missouri.

The papers in reference to the survey of Fort Wadsworth reservation have been forwarded in another communication. Captain Heap was instructed to mark out the line in front of the position of Fort Geo. H. Thomas, for the information of the troops.

Since that country is likely to increase in importance, it would be advantageous if the 49th parallel were authoritatively established, and with a view of suggesting such a result, this communication is transmitted.

WINF’D S. HANCOCK, Major General U. S. A., Commanding.

Respectfully forwarded to the Adjutant General of the Army, in the absence of the Lieutenant General.

GEO. L. HARTSUFF, Asst. Adji. General.

Official copies.

E. D. TOWNSEND, Adjt. General.
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