The Confederate militia unit Mark Twain joined for about two weeks in 1861 was the Marion Rangers.
Born Samuel Langhorne Clemens, Twain was working as a Mississippi River pilot when the Civil War disrupted river traffic. He returned to Missouri and briefly enlisted in a local Confederate unit, serving as a second lieutenant. The Marion Rangers were associated with Marion County and the pro-Confederate cause in northeastern Missouri.
Twain’s military service was extremely short. He later described the experience in the 1885 autobiographical sketch “The Private History of a Campaign That Failed,” portraying himself and his fellow volunteers as inexperienced and poorly organized. The unit disbanded after roughly two weeks, and Twain soon left Missouri to join his brother Orion in the Nevada Territory. The episode is sometimes simplified into a claim that Twain was a committed Confederate soldier, but his service was brief and became a subject of later satire and reflection.