Which ranger is known for his actions during the Civil War?

The ranger known for his actions during the Civil War is John Mosby. He was a Confederate Army cavalry battalion commander who gained notoriety for his leadership of the 43rd Battalion Virginia Cavalry, often referred to as Mosby's Rangers. His guerrilla warfare tactics, including raids behind Union lines and the disruption of supply lines, made him a significant figure in the conflict. He was renowned for his ability to operate with a small force and achieve surprisingly effective results, contributing to the overall Confederate strategy of harassing Union forces.

The other figures mentioned did not have direct involvement with the Civil War in the way Mosby did. Francis Marion, for instance, was a key figure in the American Revolutionary War, while Dan Morgan also served during that period. George Washington, as a leader in the Revolutionary War and the first President of the United States, predated the Civil War altogether, making him unrelated to this specific historical context. Thus, John Mosby stands out as the figure associated with actions during the Civil War, which makes this identification accurate and important in the study of that era's military history.