Boulder City in Clark County, Nevada — The American Mountains (Southwest)
Clear the Way of Switchyard & Towers
Journeys & Heroes
Photographed by Sandra Hughes Tidwell, September 9, 2025
1. Clear the Way of Switchyard & Towers Marker
From Water to Watts
The nearby switchyards, towers, and high voltage power lines deliver electricity from Hoover Dam generators to Southwestern cities.
The Western Area Power Administration (WAPA) operates and maintains the Hoover - Basic Magnesium North and South transmission distribution system. They regulate flow and direct hydroelectric energy to the power lines through switchyards near the dam.
Dam Power Helps Win the War
Hoover Dam served a vital role during World War II by providing massive amounts of electricity to the defense plant south of Las Vegas.
Two "sister" switchyards near the Nevada edge of Black Canyon were the starting points for the power lines serving the Basic Magnesium, Inc. 9BMI) complex. On 30 August 1942, for the first time, power from the southern Arizona Nevada Switchyard ran through the Basic South line. At the height of defense plant operation in 1943, the BMI electrical system carried one-fourth of the power generated at Hoover Dam.
Power to the People
After the war, the power lines were connected to the Nevada Power Company network to support continuing industrial production and the rapid growth of the Las Vegas Valley.
The BMI plant stopped making incendiary bombs and anti-tank weapons by mid-1944. The Basic North and South lines continued to provide electricity for the remaining industrial functions at the complexes and for Las Vegas, Henderson, and Boulder City.
Switchyard Switch Over
To build the Hoover Dam Bypass, WAPA removed the Arizona-Nevada Switchyard and rerouted its lines through the "sister" switchyard.
The Bridge Visitor Plaza parking area was once the Arizona-Nevada Switchyard. Two of its original nine towers still stand there. Its northern sister, Switchyard, called the Metropolitan Water District of Southern California (MWD) Switchyard,
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Mike O'Callahgan - Pat Tillman Memorial Bridqe
Topics. This historical marker is listed in these topic lists: Industry & Commerce • Man-Made Features • War, World II. A significant historical date for this entry is August 30, 1942.
Location. 36° 0.883′ N, 114° 44.674′ W. Marker is in Boulder City, Nevada, in Clark County. It is on Hoover Dam Access Road. Touch for map. Marker is at or near this postal address: 81 Hoover Dam Access Road, Boulder City NV 89005, United States of America. Touch for directions.
Regionally, this marker is in Nevada’s Colorado River Valley, in the Mojave Desert, and in Greater Las Vegas. It is also in the American Southwest and in the Mountain West. Globally, it is in North America, the Western Hemisphere, the Western World, and the Anglosphere. Historically, it finds itself in what was once New Spain and also Mexicos Alta California.
Other nearby markers. At least 8 other markers are within walking distance of this marker: Span The Gap with Cables 7 Arch (here, next to this marker); Protecting the Place of Nature & History (here, next to this marker); Choose the Site for Crossing & Bridge (here, next to this marker); Lay the Path with Cut & Fill (here, next to this marker); Design the Dream with Science & Art (here, next to this marker); Enjoying the Ride with Celebration & Pride (here, next to this marker); Raise the Road on Columns & Deck (here, next to this marker); America's Finest (within shouting distance of this marker). Touch for a list and map of all markers in Boulder City.
Credits. This page was last revised on October 3, 2025. It was originally submitted on September 27, 2025, by Sandra Hughes Tidwell of Killen, Alabama, USA. This page has been viewed 93 times since then and 33 times this year. Photo 1. submitted on September 27, 2025, by Sandra Hughes Tidwell of Killen, Alabama, USA. • Andrew Ruppenstein was the editor who published this page.
