Camp Hale was the only site developed by the United States Army specifically for mountain and winter warfare training. Its location provided the natural features needed for training and convenient access by both a Federal Highway and the Denver & Rio Grande Western Railroad. The large open valley accommodated more than 1,000 buildings and structures as well as parade grounds, weapons ranges, and other facilities. Construction took place between April and November 1942, and the camp officially opened on November 16. Pando Constructors recruited thousands of men and women to build the base, and as part of the work, the Eagle River was channeled through the camp. Building such a large facility in so short a time was common across the United States during World War II, but this achievement was extraordinary given the area's rugged conditions.