The 1st Minnesota sustained the highest percentage of casualties of any Union regiment in a single engagement at Gettysburg. Its extraordinary loss came during a desperate charge on July 2, 1863, the battle's second day.
As Confederate troops under Cadmus Wilcox advanced toward a dangerous gap near Cemetery Ridge, Union Major General Winfield Scott Hancock needed time to bring up reinforcements. He ordered the nearby 1st Minnesota Infantry to attack. The regiment had only 262 men available for the charge and faced a Confederate force several times larger.
The Minnesotans advanced with fixed bayonets and struck the Alabama Brigade near Plum Run. Their attack disrupted the Confederate advance long enough for Union troops to stabilize the line. Within minutes, 215 of the 262 soldiers who charged had become casualties—roughly 82 percent.
The 24th Michigan and other Union regiments suffered heavier total losses at Gettysburg, which is a common source of confusion. The 1st Minnesota is distinguished specifically by its casualty percentage during one engagement, not by the largest raw number of casualties over the entire battle.