Named for a prominent scout and explorer, this Wyoming state park encompasses a replica of an 1840s trading post, a 19th-century Army outpost, and early 20th-century automobile lodgings.

An improbable water gap where the West Walker River, paralleled by a state highway, crosses the Singatse Range between Smith and Mason Valleys.

Cross the Continental Divide through an old railroad tunnel, and ride back to the top on a shuttle.

Once owned by the largest employer in Colorado, these ovens have been abandoned for over a century.

A Native American petroglyph, the site of an emigrants' waystation, and the ruins of an early 20th-century sheep camp are all found at this crossroads.

An iron monument on the 120th meridian as surveyed, one of only four marking the boundary between Nevada and California north of Lake Tahoe.

A little-known, but surprisingly large waterfall on the Little Truckee River in the northern Sierra Nevada.

At the western edge of Palm Springs, a rugged desert canyon trail leads to a waterfall at the base of the San Jacinto Mountains.

A stretch of highway even lonelier than the so-called "Loneliest Road in America."

The only bridge in the United States where BASE jumping is legal without a permit year-round.

A remarkably well-preserved stage stop from the late 19th century in a remote part of Nevada.

A mine in the Sierra Nevada that produced nothing but barren quartz.

This open-air reconstruction of an Old West town, a cross between a theme park and a museum, provides an immersive historical experience.

A late-19th century diversion canal built by hand crosses Bryce Canyon National Park and is still in use.

Red rock "fangs" jut out of the desert near the Extraterrestrial Highway.

One of the largest wildlife refuges in the contiguous 48 states, it was instrumental in preserving the pronghorn antelope from extinction.

This lighthouse has been guiding shipping into the Golden Gate since before the American Civil War.

Beehive charcoal kilns and slag deposits mark this late 19th century camp centered on a smelter.

One of the "twins" in these falls on the Snake River was sacrificed for hydropower generation in the 1930s.

The site of an improbable and ill-fated attempt to use dammed floodwaters for irrigation.

A well-preserved sheepherding camp now lies in the heart of the Granite Chief Wilderness, in the high Sierra Nevada.

A large wind turbine installation in central Washington State is home to an extensive set of interpretive exhibits.

A remarkably well-preserved brick chimney from a smelter dating to the 1860s is all that remains of this former mill.

The only United States mine for magnesium carbonate has been operating continuously since the 1930s.