The best known Rangers of the Civil War period were commanded by the Confederate Colonel John S. Mosby. Mosby's Rangers operated behind Union lines south of the Potomac. From a three-man scout unit in 1862, Mosby's force grew to an operation of eight companies of Rangers by 1865. He believed that by the use of aggressive action and surprise assaults, he would compel the Union forces to guard a hundred points at one time. Then, by skillful reconnaissance, he could locate one of the weakest points and attack it, assured of victory. On his raids, Mosby employed small members, usually 20 to 50 men. With nine men, he once attacked and routed an entire Union regiment in its bivouac.

Equally skillful were the Rangers under the command of Colonel Turner Ashby, a Virginian widely known for his daring. The Rangers of Ashby and Mosby did great service for the Confederacy. Specialists in scouting, harassing, and raiding, they were a constant threat and kept large numbers of Union troops occupied.

Rangers who fought for the United States during the Civil War should also be mentioned. Although often overlooked in historical accounts, Mean's Rangers captured Confederate General Longstreet's ammunition train, and even succeeded in engaging and capturing a portion of Colonel Mosby's force.