The 10th Mountain Division (Light Infantry) is a light infantry division in the United States Army based at Fort Drum, New York. The division is a subordinate unit of the XVIII Airborne Corps. Originally constituted as a unique mountain warfare unit, the division was the only unit of its size in the U.S. Army to specialize in fighting in mountainous and arctic conditions, thus earning the division the "MOUNTAIN" tab. Today, the division retains its "mountain" designation for historical purposes and is organized as a light infantry division.