The following provided by Find A Grave contributor Lorena (#46917011):

Ancestry.com – US Social Security Applications and Claims Index 1936-2007
John George Cockrell; Gender: Male; Birth Date: 8 Apr 1891; Birth Place: Cora, Idaho; Death Date: 14 Jan 1956; Claim Date: 28 Nov 1956, Father: Columbus Cockrell; Mother: Henrietta; SSN: 517-10-2871; Notes: 15 Nov 1978: Name listed as JOHN GEORGE COCKRELL
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Ancestry.com – US WWI Draft Registration Cards 1917-1918
John George Cockrell; Race: Caucasian; Marital Status: Single; Birth Date: 10 Apr 1891; Birth Place: Latah County, Idaho [filed 5 Jun 1917]
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Ancestry.com – Montana County Marriages 1865-1950
John G. Cockrell; Age: 26; Birth Date: 1892; Birth Place: Idaho; Father: Columbia/Columbus Cockrell; Mother: Hattie/Hettie Griner; Marriage Date: 9 Feb 1918; Marriage Place: Havre, Hill, Montana; Spouse: Mabel M. Larsen; FHL Film #: 1902811
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Ancestry.com – US WWII Draft Registration Cards 1942
John George Cockrell; Gender: Male; Race: White; Age: 51; Date of Birth: 10 Apr 1891; Place of Birth: Cora, Idaho; Residence: Shelby, Toole, Montana; Mailing Address: General Delivery, Olney, Flathead, Montana
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Great Falls Tribune
Great Falls, MT
Monday, January 23, 1956
Page 4, Column 2

Treasure State Deaths

John G. Cockrell

WHITEFISH – Word was received of the death in Shelby of John G. Cockrell, former Whitefish resident. Cockrell, who farmed extensively in the Marias River area south of Galata, died of a heart attack. Burial was in Shelby.

While living in Whitefish between 1920 and 1930, Cockrell worked for the Hutchinson Bros. saw mill east of town. Later he lived in the Olney area before moving to Shelby. He was a brother of Mrs. William Fry and Mrs. W. J. Simpson, both of Whitefish.

In addition to his sisters here, Cockrell is survived by the widow and son and two daughter at Shelby and son, Marvin, Kalispell.

Mrs. Simpson attended the funeral services. Because of illness, Mrs. Fry was unable to attend.
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Ancestry.com – Montana Death Index 1868-2011
John G. Cockrell; Birth Year: abt 1892; Death Date: 14 Jan 1956; Death County: Toole; Age at Death: 64
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The following provided by Find A Grave contributor, RunninonMT:

"A Documentary and Biography of the Cockrell Family Name Compiled February 1, 1985" by Claude R. Cunningham:
Children of Columbus Jefferson Cockrell and Henrietta Griner -
"(#5) John George Cockrell - born April 10, 1891 at Gardner, Idaho. Married Mabel Minnie Larsen February 9, 1918. Six children were born of this marriage, Jack, Marvin, ______, Darlene, Jerry and Joan. Both John and Mabel are buried at the Mountain View cemetery Shelby, Montana."

All five of the named children are deceased. The sixth child has not been named out of privacy concerns.

Claude R. Cunningham, memorial #20302178, is the nephew of John and Mabel Cockrell, and the grandson of Columbus and Hettie Cockrell.