Battle of South Mountain
The Iron Brigade was the only named brigade to come from varied states, the 2nd, 6th, and 7th Wisconsin Infantry, along with the 19th Indiana Infantry and was formed on October 1, 1861. Although at the time, it wasn't known by this name, simply known as 3rd Brigade, I Corps. It wouldn't earn the moniker for almost a year, during the Battle of South Mountain during the Antietam Campaign.