John P. Slough was born in Ohio in June 1856, the son of John P. and Arabella Slough. He enlisted in the army in July of 1872 and re-enlisted in November 1877. He served as a clerk. He was in the 2nd U. S. Cavalry at the Black Hills Expedition in October 1875 and the Big Horn Expedition in March 1876. After leaving the military he was a railroad claims clerk in St. Louis, Missouri. He died May 13, 1927 and is buried at Jefferson Barracks National Cemetery in Missouri. [CHECK WITH COLLECTION!!]
From the description of John P. Slough papers, 1866-1922. (Montana Historical Society Library). WorldCat record id: 428982677