On July 2, 1863, at the Battle of Gettysburg, the 20th Maine under the command of Colonel Joshua Lawrence Chamberlain held the far left of the Union line.

In a desperate attempt to "roll up" the Union flank, the 15th Alabama repeatedly assaulted Chamberlain’s line only to be repulsed each time. Out of ammunition, the shout of "Bayonet" from Col. Chamberlain was heard up and down the line, and the men from Maine rose up and charged.

This bold counterattack won Col. Chamberlain the Medal of Honor.