John Kingery (My First Cousin Five Times Removed) enlisted in the United States Army in September, 1861. He was in Company E, 116th Illinois Volunteers*. He served for two years and eight months. On May 27, 1883, John Kingery was mustered into the Grand Army of the Republic. At the time of his death, he was the Commander of the G.A.R. Post of Monroe (Post # 84). * It is said (in the Kingery Family Book, published by Ben Kingery in 1995) that John Kingery served in Company E of the 116th Illinois. On his headstone, and other websites, it is said that he served in Company A of the 106th Illinois Volunteers.
According to a search I did on the Illinois Secretary of State website, there was a John S. Kingery in Company E of the 106th Illinois Infantry. It wouldn't be the first time I had seen a grave marker with the wrong unit engraved on it. If that is your relative, I am inclined to go with the SoS website, since it seems to be based on muster rolls of the respective units.