The Quartermaster's Office housing the Lewis Armistead Museum is the only building left from the original military fort. The quartermaster and second in command at Fort Dodge was Brevet Major Lewis Addison Armistead, a career army man from an illustrious military family.
His father had been a general in the U.S. Army and his uncle had commanded Fort McHenry when Francis Scott Key composed the "Star Spangled Banner" as the fort was under attack during the War of 1812. Lewis himself had received his brevet for bravery exhibited during the Mexican War shortly before he arrived in Fort Dodge with the Sixth Infantry.
When the army left Fort Dodge in 1853, Armistead moved with them, eventually serving in California on the eve of the Civil War. Like most of the other officers of Southern birth, Armistead resigned his commission in the U.S. Army to serve in the Confederacy when the war broke out. He rose to the rank of Brigadier General and was mortally wounded leading the last wave of Pickett's Charge at the Battle of Gettysburg on June 3, 1863. The poignant story of Armistead facing the forces of his best friend, General Winfield Scott Hancock, U.S.A., on the battlefield at the "High Tide of the Confederacy" is a moving story of America's bloodiest conflict.

The recently released motion picture "Gettysburg" featured Armistead prominently as portrayed by actor, Richard Jordan. The Office at the museum today displays mannequins showing Armistead as the Adjutant of Fort Dodge in his office setting and as a Brigadier General of the Confederacy. Also on exhibit are numerous works of art highlighting Armistead's heroic performance at the Battle of Gettysburg including a copy of the Masonic Memorial at the National Battlefield.