Civil War Heroine Sarah Emma Edmonds, who disguised as a man, became a spy for the Union side. Ironically, she often went undercover as a woman (making her a woman disguised as a man disguised as a woman) in order to get behind enemy lines.
Union sharpshooters were the elite marksmen of the army. Their green uniforms and rubber buttons were an early attempt at camoflage. To qualify a rifleman had to put 10 out of 10 shots into a 10 inch circle at yards.