Ruby Canyon is a roughly 25 mile (40 km) long canyon

Canyon

A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of...

 on the Colorado River

Colorado River

The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

 located on the Colorado

Colorado

Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

-Utah

Utah

Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

 border in the western United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, and is a popular destination for rafting

Rafting

Rafting or white water rafting is a challenging recreational outdoor activity using an inflatable raft to navigate a river or other bodies of water. This is usually done on white water or different degrees of rough water, in order to thrill and excite the raft passengers. The development of this...

. The canyon takes its name from the red sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 cliffs which line the canyon walls.
The only access to the canyon outside of rafting is provided by Union Pacific Railroad

Union Pacific Railroad

The Union Pacific Railroad , headquartered in Omaha, Nebraska, is the largest railroad network in the United States. James R. Young is president, CEO and Chairman....

 (formerly Denver and Rio Grande Western Railroad

Denver and Rio Grande Western Railroad

The Denver & Rio Grande Western Railroad , often shortened to Rio Grande or D&RGW, formerly the Denver & Rio Grande Railroad, is a defunct U.S. railroad company. The railroad started as a narrow gauge line running south from Denver, Colorado in 1870; however, served mainly as a transcontinental...

) between Mack, Colorado

Mack, Colorado

Mack is an unincorporated town and a U.S. Post Office located about 10 miles east of the Colorado/Utah border in Mesa County, Colorado, United States. The Mack Post Office has the ZIP Code 81525...

, and Westwater, Utah. Amtrak

Amtrak

The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...

's California Zephyr

California Zephyr

The California Zephyr is a long passenger train route operated by Amtrak in the midwestern and western United States.It runs from Chicago, Illinois, in the east to Emeryville, California, in the west, passing through the states of Illinois, Iowa, Nebraska, Colorado, Utah, Nevada, and California...

follows this route through Ruby Canyon between Grand Junction, Colorado

Grand Junction, Colorado

The City of Grand Junction is the largest city in western Colorado. It is a city with a council–manager government form that is the county seat and the most populous city of Mesa County, Colorado, United States. Grand Junction is situated west-southwest of the Colorado State Capitol in Denver. As...

, and Thompson Springs, Utah

Thompson Springs, Utah

Thompson Springs, also known as Thompson, is a small census-designated place in central Grand County, Utah, United States. The population was 39 at the 2010 census. The town is just north of the east-west highway route shared by Interstate 70, U.S. Route 6 and U.S. Route 50, between Crescent...

. A popular attraction along the route are the words "Utah Colorado" painted on the canyon wall at the border between the two states next to the Utaline Siding

Rail siding

A siding, in rail terminology, is a low-speed track section distinct from a running line or through route such as a main line or branch line or spur. It may connect to through track or to other sidings at either end...

.