Boulder City in Clark County, Nevada — The American Mountains (Southwest)
Protecting the Place of Nature & History
Journeys & Heroes
Photographed by Sandra Hughes Tidwell, September 9, 2025
1. Protecting the Place of Nature & History Marker
Plants & Wildlife
The contractors protected or moved native plants before starting to build. They collected many plants and stored them in a nursery. Later, they replanted vegetation on the site. Environmentalists also harvested seeds of some plants to spread and sprout after contractors finished site work.
The engineers designed road underpasses as wildlife crossings. The new approach to highways would have blocked the routes that desert bighorn sheep follow for feeding and breeding. High fences along the highway guide wildlife to the underpasses. These features greatly reduce the chance for vehicles to strike the sheep.
Air & Water
The Baypass Project improves air quality at the Hoover Dam by allowing through-traffic to cross Black Canyon quickly.
Large numbers of vehicles no longer slowly crawl down and up the steep canyon walls to cross over Hoover Dam. The old route caused cars and trucks to burn great amounts of fuel and to pollute the air. They made more exhaust fumes while stuck in traffic jams on the dam.
The Bypass Project removes vehicles carrying hazardous materials from atop the dam and reduces the chances of spills. Water drains off the River Bridge into basins at its ends. It does not flow directly into the river.
Historic & Cultural Resources
The Bypass Project respects the important resources of the Hoover Dam National Historic Landmark.
The River Bridge and roadways blend with the Hoover Dam and its setting. The engineers moved the highway route to avoid tearing down the historic Reclamation warehouse. Construction could not avoid relocating or removing some historic features, such as the Arizona-Nevada Switchyard and towers. The historians recorded those structures in historical narratives and detailed photographs. They also documented Native American traditional
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Mick O'Callaghan - Pat Tillman Memorial Bridge
Topics. This historical marker is listed in this topic list: Bridges & Viaducts.
Location. 36° 0.882′ 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 Rd, 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); Choose the Site for Crossing & Bridge (here, next to this marker); Clear the Way of Switchyard & Towers (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 October 2, 2025, by Sandra Hughes Tidwell of Killen, Alabama, USA. This page has been viewed 60 times since then and 19 times this year. Photo 1. submitted on October 2, 2025, by Sandra Hughes Tidwell of Killen, Alabama, USA. • Andrew Ruppenstein was the editor who published this page.
