The 100th Indiana was one of the regiments engaged at Tunnel Hill. It was part of Loomis' Brigade of Ewing's Division of the 15th Corps. Two of its officers, Major Ruel Johnson and Captain Charles Brouse, received the Congressional Medal of Honor for their conduct in the battle. Peter Cozzens gives a good account of the struggle for Tunnel Hill in his book The Shipwreck of Their Hopes: The Battles for Chattanooga. I have a picture of the marker near Tunnel Hill that mentions the 100th Indiana. If you’d like a copy of it just email me and I’ll send it to you.