Historic Railroad Trail

two people walking through tunnel

NPS Photo by Andrew Cattoir



The Historic Railroad Trail is an easy, dog-friendly hike along a former railroad grade. It provides panoramic views of Lake Mead, overlooking the Boulder Basin area. As hikers travel through five large tunnels, they will experience a portion of the railroad route that ran from Boulder City to Hoover Dam from 1931 to 1961.

As one of Southern Nevada’s most unique trail experiences, the trail was designated as a national recreation trail on June 4, 2015. It shares the rich history of the construction of the Hoover Dam and the creation of Lake Mead.

In 2017, the Historic Railroad Trail was graded and received a new layer of decomposed granite, improving its accessibility and the overall visitor experience. The trail can be accessed near the Lake Mead Visitor Center or via the Hoover Dam Parking Garage.


  • The first tunnel is around 1 mile from the trailhead.
  • The fifth tunnel is around 2.2 miles from the trailhead.
  • The elevation change from the trailhead to the fifth tunnel is about 11 feet.
  • After the fifth tunnel, the trail continues another 1.5 miles to the Hoover Dam Parking Garage. The elevation change between these two points is around 445 feet.
  • Total distance = 7.5 miles (12 kilometers) round trip.

Fun Facts

Only remaining section of Hoover Dam Railroad system that is not highly disturbed or under water.

All tunnels are approximately 300 feet in length, and 25 feet in diameter. The tunnels were oversized to fit penstock sections and large equipment being transported to Hoover Dam.

Nine steam and four gas locomotives and 71 people were used to operate the system. It was a standard-gauge, 90-pound rail construction that used Oregon fir ties.

This section of the railroad was used in the motion picture "The Gauntlet" starring Clint Eastwood and Sondra Locke for a sequence in which they were on a motorcycle being chased by an assassin in a helicopter.

visitor center map graphic
The Historic Railroad Tunnel Trail is located near the Alan Bible Visitor Center

Historic Railroad Trail


woman sitting on bench by bike looking at lake mead

NPS Photo by Chelsea J. Kennedy


In 1931, a construction contract was let to Six Companies, Inc., a consortium of six major western firms. Together with the government, they built almost 30 miles of railroad connecting Boulder City with all the facilities needed to build Hoover Dam (eg., cement mixing plants, quarry pit, gravel sorting plant). The Hoover Dam construction railroad system had three segments. The first, from Las Vegas to the Boulder City site, was built and operated by the Union Pacific Railroad.

The second segment was built by the U.S. Government. It ran from Boulder City down Hemenway Wash to Himix, the concrete mixing plant on the rim of the Black Canyon overlooking the dam. It provided concrete for the final 242 feet of the dam and the buildings on its crest. The airline distance from Boulder City to Himix was 6.7 miles. A drop of 1,100 feet in elevation however, necessitated ten miles of winding tracks to keep the grades from being too steep.

Six Companies, Inc. built and operated the third segment of the system. The tracks branched off the U.S. Government Construction Railroad at Lawler, about a mile up Hemenway Wash from the Visitor Center. It crossed Hemenway Wash and followed the base of the River Mountains and then looped eastward to the gravel plant on the flat overlooking the Colorado River. One branch went upstream 7.3 miles from the gravel plant to the gravel beds on the Arizona side.

Isolation demanded the tons of concrete needed for the dam to be manufactured locally. An electric dragline with a five cubic yard capacity loaded gravel into railroad cars. Concrete was made by mixing sand and crushed rock, called aggregate, with Portland cement and water. More than four million cubic yards of aggregate were taken from the Arizona side of the river. The other branch followed the river downstream into Black Canyon, to Lomix, a concrete mixing plant situated at the base of Black Canyon. Lomix provided the concrete for the diversion-tunnel linings, the powerhouse foundation, and two-thirds of the dam. To prevent the concrete from drying during transportation the mixing plant was put as close to the river as possible. Locomotives hauled tons of gravel to a screening plant on the other side of the river 24-hours a day. A round trip took slightly more than two hours.

The Six Companies, Inc. Railroad was abandoned after the completion of Hoover Dam in 1935. The U.S. Government Construction Railroad section was sporadically used until 1961, when the last generator was hauled over its rails and installed at the power plant.

Lawler Junction

As you stand in the trailhead parking lot below the Lake Mead Visitor Center, it is hard to believe that in the 1930s during the Boulder Dam Construction, that this was a busy railroad switch yard. If you look hard you can still see remains of the railbed. The trail from this parking lot going east to the dam is built on the spur going to the the “Himix” site above the dam. The trail going west under the road, the River Mountains Loop Trail, follows the the old rail bed 3.5 miles uphill into Boulder City. The original rail line ran 10 miles up into Boulder City, meandering through Hemenway Wash to keep the grade at or below 4 percent. Most of the line within Boulder City has been consumed by development. Lawler Junction was also known as "U.S. Government Junction."

From Lawler Junction, the railroad went north for 7 miles to Saddle Island and then east to a gravel plant that is now submerged under the lake. From the gravel plant, the line split into two branches. One line ran south for 4.8 miles to Hoover Dam via Cape Horn to Lomix (Lower Level Concrete Mixing Plant). The second line ran north from the gravel plant 7.3 miles across the Las Vegas Wash and crossed the Colorado River over a bridge into Arizona to the Arizona gravel pits located across from Callvlle.

man in wheelchair on trail

“I did the 2.1 miles from the trailhead to the Bureau of Reclamation boundary and back in my wheelchair. This trail was previously off limits to me. I liked the firmness and its natural, esthetically pleasing appearance. It is beautiful. I was especially pleased with the consistent evenness through the tunnels which gave me confidence while safely rolling through the nearly dark places."
--Ed Price, Accessible Trails Foundation

The Trail

You can walk, run, bicycle or even push a stroller on this flat easy trail. Along the trail you will see a section of rough, rocky road on the south side of the railroad bed that is believed to be the first section of pioneer trail or road for the construction of Hoover Dam. Approaching Tunnel 1, on the right, look down the ravine to see concrete plugs taken out of Hoover Dam to install the turbines.

Tunnel 1 has eight sections of vertical supports, five of which have horizontal planks to prevent the fall of loose rock on to the tracks so there would be few delays during the 24-hour dam building schedule. Weight from the rock has damaged the outermost, eastern arch.

Tunnel 2 burned in an arson fire in 1990. You can see it looks different from the other tunnels. It was sprayed with shotcrete to fortify the now looser rock.

Rocks excavated from the tunnels were undoubtedly used for the fills. The outermost east arch was deformed by pressure of the rock in tunnel 3.

Tunnel 5 was burned in 1978 and was then sealed. The tunnel was restored, sprayed with shotcrete and reopened in July 2001. The trail continues to Hoover Dam and the visitor center parking structure. The gates after Tunnel 5 are locked at sunset.

All tunnels are 25 feet in diameter. They were oversized to fit huge penstock sections and large equipment being transported to Hoover Dam.

Nine steam and four gas locomotives and 71 people used to operate the system. It was a standard-gauge, 90-pound rail construction that used Oregon fir ties.


Leave no trace

  • Stay on designated trails
  • No motorized vehicles
  • Carry out all food and trash
  • Leave rocks, plants and artifacts where you find them
  • The gates after Tunnel 5 are locked at sunset
  • Dogs are allowed on the trail, but not on the Dam Visitor Center parking area
  • Keep dogs on a six foot leash at all times
  • Bring and use dog waste bags
  • Respect all wildlife

suggested packing list

  • Water
  • Energy snacks
  • Map
  • Hiking hat or biking helmet
  • Sturdy shoes
  • Tire patch kit and air pump
  • Sunglasses
  • Sunblock
  • Lip protection
  • Garbage bag
Historic Railroad Trail

Last updated: January 24, 2018

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