The Illinois National Guard reports that "previously unknown Black Hawk War documents written and signed by Capt. Abraham Lincoln while on duty in 1832, and an affidavit signed by Lincoln in 1855, have recently been discovered at the National Archives in Washington, D.C., and their authenticity confirmed by researchers at the Abraham Lincoln Presidential Library and Museum in Springfield, Ill."
Lincoln is one of 19 presidents to serve in a state national guard (or as it would have been called in his time, state militia). Lincoln enrolled in 1832 on the occasion of a number of clashes known to history as the Black Hawk War. He was elected captain in the 31st Regiment of Militia of Sangamon County, 1st Division and in command of the 4th Regiment of Mounted Volunteers, a rifle company. Lincoln and his men saw no combat, though they arrived at the site of the Battle of Stillman's Run in present-day Ogle County, Illinois, not long after that battle, and helped bury the dead.
Later, Lincoln (as his wont) joked about this time in the militia: "I had a good many bloody struggles with the mosquitoes, and although I never fainted from the loss of blood."
The Illinois National Guard explains that "private researcher Anne Musella recently brought a previously discovered Certificate of Discharge signed by Lincoln to the attention of Papers of Abraham Lincoln staff who are working at the National Archives Building in downtown Washington. That led Assistant Editor David Gerleman to delve further in the Bounty Land Warrant files at the National Archives, where he found two more Certificates of Discharge written and signed by Lincoln.
"Together with other documents previously discovered, it appears that Lincoln, like other officers, filled out and signed dozens of these Certificates of Discharge. Given to soldiers as they mustered out to return home, the veterans later submitted these documents as proof of service when they claimed the bounty lands allotted to them by Congress. The certificates located at the National Archives more than double the number of surviving discharge certificates written and signed by Captain Abraham Lincoln, and likely others still await discovery."