The 20th Maine Volunteer Infantry Regiment was a regiment of the US Army that was active from 20 August 1862 to 16 July 1865. The regiment was organized in the US state of Maine and was mustered into service with Adelbert Ames as its commander. The regiment was taken over by Joshua Chamberlain in May 1863 after Ames was promoted, and it fought with valor at the Battle of Gettysburg in July 1863, defending Little Round Top despite heavy losses and a lack of ammunition. The regiment drove the Confederates back with a bayonet charge, and Chamberlain became a war hero for his leadership of the regiment. The regiment would fight in Virginia and end the war at Appomattox; during the war, 1,621 men served in the regiment, which lost 147 dead from war, 146 dead from disease, 381 wounded, and 15 captured.