Timpanogos Cave National Monument was established in 1922 to protect and provide public access to a series of exotic caves in American Fork Canyon. The interior of the caves is decorated with a colorful variety of dripstone, flowstone, and rimstone formed by minerals in the ground water that enters the caves.

The monument consists of three caves connected by manmade tunnels. Hansen Cave was the first to be discovered, in 1887, followed by Timpanogos Cave in 1915 and Middle Cave in 1921. During the 1890s Hansen Cave was stripped of most of its onyx and other mineral deposits by crews working for a Chicago onyx company. After the other two caves were discovered, local groups and the Forest Service were determined to protect them from the same fate. Designation of the site as a national monument provided the necessary protection.

A number of improvements have been made over the years to make the cave more accessible to the public. A trail was constructed and electric lights were installed in the cave in 1921, and a campground, parking area, and ranger's residence were built in 1922. These facilities have been upgraded periodically, and new improvements were made as well, such as the installation in 1923 of a telephone system between the base and the cave entrance in order to better coordinate tour groups and guides. The three separate caves were joined by short tunnels in the 1930s, allowing a more efficient, one-way flow of visitors.

Though the cave originally was under the jurisdiction of the Forest Service from 1922 to 1934, and then the National Park Service from 1934 on, it was actually operated for twenty-four years by the Timpanogos Outdoor Committee, a group of local businessmen. Under this unique arrangement, the cave superintendent was not officially an employee of the government, although he wore an official uniform and lived in a house provided by the federal government. The committee operated the cave as a not-for-profit enterprise, using the proceeds from cave admissions to maintain and upgrade the site. In 1947 the National Park Service assumed complete control over the cave operation and has continued to manage it to the present. Timpanogos Cave National Monument continues to draw thousands of visitors each year during its months of operation--May through October.