This collection consists of Marcus de Lafayette Simpson’s correspondence while stationed at Fort Leavenworth, Kansas during 1858. His correspondence is contained in a record ledger which spans April to September and consists of approximately one-hundred letters which discuss troop and supply movements between Fort Leavenworth, the Utah Territory, and the surrounding area. His letters also discuss conditions at Fort Leavenworth, the Utah War, Mormons, Native American Indian relations, and other similar topics. In July of 1858 Simpson traveled to Salt Lake City on official business with a supply train, where he stayed for the period of one week.

This collection also contains an 1860 government publication entitled Statistical Report on the Sickness and Mortality in the United States Army, which discusses conditions at Fort Leavenworth (pages 93-96), troops in the Utah Territory (281-328), and general conditions in the area.