The Ancestry.com database "Headstones Provided for Deceased Union Civil War Veterans, 1879-1903" record for Salem Aitken shows a death date of July 29, 1887, and burial at Crow Wing, Minnesota.

No obituary was found in the Brainerd Dispatch of 29 July 1887, 05 August 1887, or 12 August 1887.

The Civil War Pension Record Index (see image) shows that "Ellen" applied for the Widow's benefit 05 Sep 1890 and his mother, Om-te-te-won-o-quay, applied for her own benefit 05 Oct 1891.

Salem Aitken and Eustach Jourdon were originally buried in the Catholic Mission Cemetery at Old Crow Wing. As the village was abandoned after the 1870s, their remains were moved to Rock Island National Cemetery (so the story goes) and their Civil War Veteran monuments were moved to Evergreen.

For Ojibwe band related information, see:
http://www.ojibwe.info/...#I4029.

Ancestry.com "U.S. Civil War Soldier Records and Profiles":
Name: Salem Aitkin
Age at enlistment: 24
Enlistment Date: 16 Aug 1862
Rank at enlistment: Private
Enlistment Place: Fairbanks, Crow Wing Co., MN
State Served: Minnesota
Survived the War?: Yes
Service Record: Enlisted in Company G, Minnesota 9th Infantry Regiment on 16 Aug 1862.
Mustered out on 06 Oct 1863.
Birth Date: abt 1838
Sources: Minnesota in the Civil and Indian Wars 1861-65
Minnesota Adjutant General's Report of 1866

Ancestry.com "American Civil War Soldiers":
Name: Salem Aitkin
Enlistment Date: 16 Aug 1862
Enlistment Place: Fairbanks, Crow Wing Co., Minnesota
Side Served: Union
State Served: Minnesota
Service Record: Enlisted as a Private on 16 August 1862 at the age of 24.
Enlisted in Company G, 9th Infantry Regiment Minnesota on 16 Aug 1862.
Received a disability discharge from Company G, 9th Infantry Regiment Minnesota on 6 Oct 1863.

1850 census for Sauk Rapids, Benton, Minnesota, family #8:
Aitken, William A., 58, b. Scotland
Aitken, Roger, 23, b. Minnesota
Aitken, Selim, 11, b. Minnesota
Aitken, Robert, 8, b. Minnesota
Aitken, Edgar, 3/10, b. Minnesota
Aitken, Julia, 13, b. Minnesota
Aitken, Mamima(Fem), 6, b. Minnesota
Aitken, Childe(Fem), 4, b. Minnesota
Aitken, Isabella, 2, b. Minnesota
(Mamima seems to be Amanda in 1860.)

1860 census for Crow Wing Township, Crow Wing, Minnesota, family #24:
La Rue, Charles W., 24, b. NY, Tavern Keeper
La Rue, Julia E., 20, b. Minnesota
La Rue, Nancy M., 3, b. Minnesota
La Rue, Robert F., 2, b. Minnesota
Dumphry, James, 26, b. New Brunswick, Teamster
Aitkins, Robert, 20, b. Minnesota, Terrant(?)
Aitkins, Isabil, 14, b. Minnesota, Terrant(?)
Aitkins, Childa, 16, b. Minnesota, Terrant(?)
Darby, Charles, 22, b. England, Laborer
Horn, William, b. Maine, 23, Laborer
(Julia might be the former Julia Aitkins.)
Family #25:
Adams, Joseph, 35, b. B. America, Voyager
Adams, Julia, 40, b. Minnesota
Adams, Joseph, {blank), b. Minnesota
Aitkins, Selim, 25, b. Minnesota, Voyager
Aitkins, Amanda, 17, b. Minnesota
Masterson, Helen, 7/12, b. Minnesota
(Amanda is Selim's sister, not his wife.)

1870 census for Chippewa Agency, Cass county, Minnesota, family #20:
Aitkins, Mary, 50, b. Minnesota, Sewing & washing
Aitkins, Amanda, 30, b. Minnesota
Aitkins, Isabel, 26, b. Minnesota
Aitkins, Joseph, 18, b. Minnesota
Aitkins, John, 3, b. Minnesota
(Mary is very likely the Mary who is the mother of at least Amanda and Isabel and the mother of Selim/Salem. See http://www.ojibwe.info/...#0I4028.)
(Selim/Salem is not found in the 1870 census - perhaps he was out voyaging.)

1880 census for Brainerd, E.D. 99, family #343:
Aitken, Salem, 43, head, b. Minnesota
Aitken, Carlotta, 37, wife, b. Minnesota

1885 MN census for Crow Wing Townships 44 & 45, family #73
Aiken, Roger, 57, b. Minnesota
Aiken, Mary, 58, b. Minnesota
(4 others omitted)
Family #73 (sic - number repeated)
Aiken, Salem, 47, b. Minnesota
Aiken, Sarah, 47, b. Minnesota
(Township 44 is Crow Wing, and 45 is outside the city limits of Brainerd.)