The Leach family papers consist of photocopies of letters, and a ledger/scrapbook belonging to Morgan Leach. The early letters (1810-1827) discuss the hardships of pioneer life, the swift deaths brought on by disease, and the loneliness of separation from families left behind. The later correspondence discuss business and land transactions, teachers' wages, and various aspects of small town life. Clinton's letters to his parents in 1841, when he went from Margaretta, Ohio to Grand Blanc, Michigan include detailed description of the places he traveled through and the cost and means of transportation at the time.

Morgan Leach's ledger records the credit accounts of his customers between 1845 and 1851 when he worked as a peddler. The ledger was later used as a scrapbook for newspaper clippings of letters he wrote to the Clinton County Republican while serving in the Civil War while he was serving with the 1st Michigan Cavalry. He described the hardships of camp life, the cold damp weather, and the lack of adequate provisions (blankets, overcoats, etc.) which contributed to widespread disease and death. He commented on the encouragement and hospitality shown by both Northerners and Southerners. Often expressing his political views, Dr. Leach recounted the battle of Winchester in April, 1862 when he was ambushed and presumed dead while tending to patients on a Union train. The final two letters discussed the low morale of the troops in 1862 resulting from the retreat of the Union army to Washington D.C. and the poor war effort. Warning that the Union could lose the war, Leach advocated recruiting and arming blacks and all able-bodied white males.