Perhaps the regiment's finest hour came at Gettysburg, where it lost 77% of its strength (233 casualties out of 302 effectives) in stubborn fighting on McPherson's Ridge during the Iron Brigade's lengthy action on July 1, 1863. Colonel Fairchild lost an arm due to severe wound, and most of the line officers went down as well. The regiment reformed on Culp's Hill and entrenched for the rest of the battle. Although the 2nd Wisconsin was able to replenish some of its losses, it was never the same fighting force again. It later served in the Bristoe and Mine Run campaigns. The final campaign for the 2nd Wisconsin was Grant's bloody Overland Campaign.