The National Park Service had high hopes for the replacement of the Yellowstone River Bridge. As the park prepares to close most of its roads for the winter season, a crucial milestone is being reached.
The immense steel beams that will support the flow of tourist traffic across the Yellowstone River are being installed across the entire 1,285-foot expanse. That brings the project closer to its November 2026 target, but traffic will flow over the bridge sooner than that.
“All the steel girders are on site,” Daniel Rhodes, a landscape architect with Facility Management and Operations in Yellowstone, told Cowboy State Daily. “Weather permitting, we hope to have them all set right before Thanksgiving.”
New Heights
The $118 million project to replace the Yellowstone River Bridge began in 2023. The new bridge will replace the existing one, which was built in 1961 and is showing signs of age.
Rhodes said this is the biggest project he’s been involved with in Yellowstone so far.
“The Pelican Creek viaduct we finished in 2020 is 1,500 feet long, but it's only 17 feet high,” he said. “The existing Yellowstone River Bridge is 604 feet long, while the new bridge is 1,285 feet long and sits 180 feet above the river.”
That makes the new bridge comparable to the Gardiner River Bridge near the North Entrance, which is 962 feet long and stands 201 feet above the river.
Yellowstone hasn’t undertaken a project at these heights since the 1930s, when the Gardner River Bridge was built. Rhodes said making the new bridge much taller was the easier, safer, and less intrusive option for the critical road corridor.
“The pillars allow the bridge deck to be up to the top of the Yellowstone River Canyon,” he said. “This minimized the excavation we had to do on each side of the bridge. The old bridge drops down the steep grade on both approaches. The new design was done to keep the grades level.”
The towering concrete pillars rose during the summer, using cranes one expects to see building skyscrapers in New York or Denver. An aerial view of the construction site shows a much smoother ride across the expanse of the Yellowstone River Canyon.
Steel Delivery
Now that the three concrete pillars have reached the necessary height of 160 feet, massive steel girders are being placed across them. Rhodes said the girders are 9-15 feet tall and 100 feet long.
“They are huge,” he said. “The steel girders go on top of the concrete piers, and then the concrete deck that the roadway will be built on will go on top of the girders.”
The logistics of getting the girders to the construction site were complicated. Rhodes said a route through the park had to be carefully planned to ensure the steel beams could be safely moved without damaging any infrastructure.
“They came in through the West Entrance and then up over Dunraven Pass,” he said. “A couple of bridges north of Madison Junction wouldn't support the weight, so we brought them up and over Dunraven.”
Transporting the girders from West Yellowstone to the construction site at Tower Junction was planned during low-traffic hours, usually early in the morning, to reduce traffic impacts. The trucks carrying the 100-foot girders had to be cautiously escorted along the narrow, winding roads to reach their destination.
“It is quite an orchestra that we coordinate,” Rhodes said. “The park, the contractor and bridge engineers from the Federal Highways Administration all worked together to determine the bridge load ratings and came up with the predetermined route. And they all made it.”
A Higher Compromise
Rhodes believes the new Yellowstone River Bridge will be “a big improvement” over the existing bridge. But, as with every major park project, there were some compromises that will change the experience of crossing the Yellowstone River.
“It's a constant battle of safety versus what the public wants to see,” he said. “But what the public wants is always a consideration.”
One significant difference between the two bridges is that the existing bridge is much closer to the river. The new bridge will be much higher, making the river and the canyon seem more distant.
Rhodes said safety and reducing the bridge’s impact on the landscape were the priorities during design, which made a taller bridge preferable to the existing one. Nevertheless, the new bridge has been designed to offer a similar experience for visitors and the local wildlife.
Rhodes said the Yellowstone River picnic area is being expanded as part of the project. A Yellowstone River Canyon trail will be established, offering “excellent views” of the river and canyon, in addition to the walkways on the bridge itself.
“There'll be parking on both sides of the bridge, and people can walk across the deck if they want to,” he said. “There will be safety dividers between the roadway and the walkways to keep the public as safe as possible when they walk across the deck.”
Those safety dividers will be a welcome addition for the bison. The Yellowstone River Bridge is a popular migration corridor for Yellowstone’s bison, something they’ve reminded the construction crews of many times.
“We’ve had to hold up traffic a lot just because the bison are on the bridge deck,” he said. “The old bridge is a big bison corridor, and we anticipate that continuing with the new bridge.”
Work progresses on a massive $118 million project to replace the Yellowstone River Bridge in the national park. The new bridge will be 180 feet tall and 1,285 feet long. (Courtesy Yellowstone National Park) 
Work progresses on a massive $118 million project to replace the Yellowstone River Bridge in the national park. Here a pair of workers stand on the lip of one of the massive I-beams for the bridge. (Courtesy Yellowstone National Park) 
Work progresses on a massive $118 million project to replace the Yellowstone River Bridge in the national park. The new bridge will be 180 feet tall and 1,285 feet long. (Courtesy Yellowstone National Park) 
Work progresses on a massive $118 million project to replace the Yellowstone River Bridge in the national park. The new bridge will be 180 feet tall and 1,285 feet long. (Courtesy Yellowstone National Park) 
Work progresses on a massive $118 million project to replace the Yellowstone River Bridge in the national park. The new bridge will be 180 feet tall and 1,285 feet long. (Courtesy Yellowstone National Park) 
Work progresses on a massive $118 million project to replace the Yellowstone River Bridge in the national park. The new bridge will be 180 feet tall and 1,285 feet long. (Courtesy Yellowstone National Park)
Year-Round For Another Century
The road between the North and Northeast Entrances is the only road in Yellowstone that is open and maintained year-round, which was an essential factor in the design and construction of the new Yellowstone River Bridge.
“The bridge engineers at the Federal Highway Administration say their designs are made to last 75 to 100 years under normal wear and tear,” he said. “There's a lot of overdesign on every bridge for safety purposes, but the current estimate is this bridge will last for at least that long.
That’ll be important once the new bridge opens for traffic. It will support a constant flow of traffic across a vital lifeline for the communities of Cooke City and Silvergate during the intense winter seasons.
In addition to new parking areas, a new junction is also being built across from the Roosevelt Corrals. It will be slightly closer to Tower Junction and connect to the existing Northeast Entrance Road to ensure easier traversal and maintenance.
“Everything’s been factored in,” Rhodes said. “That road is open 12 months a year, so the bridge's height keeps the grades level for safer winter travel.”
Opening A Bridge And Lost Creek
“The big push” to finish the new Yellowstone River Bridge will begin next spring. Rhodes said a precast deck panel will be placed on top of the steel girders, which another layer of concrete will cover to complete the bridge deck.
If everything goes according to schedule, Rhodes hopes to have traffic on the bridge by the end of 2025. The only unfinished business will be removing the existing bridge, which will be finished by November 2026.
“We have to dismantle the old bridge and all the existing roadway associated with it,” he said. “We’ll start at one end and cut it into manageable pieces, and the piers will be the last thing taken down.”
The removal of the 1939 bridge will allow for some important landscape reclamation. Rhodes said the final aspect of the $118 million project will be restoration of the Lost Creek Drainage.
“The Lost Creek Drainage was impacted when the original road went in, and we're going to restore it to its natural function,” he said. “That'll be an important part of the restoration as we take that previous road corridor out.”
On The Other Side
The Yellowstone River Bridge project is one of the most expensive construction projects in Yellowstone’s history. However, it’s already looking to be overshadowed and outspent by what Rhodes sees further along the road.
“We're currently designing a permanent Mammoth-Gardiner Road,” he said. “That's looking to be quite a bit bigger than this project. The Yellowstone River Bridge is the most expensive project to date, but I think the new permanent Mammoth-Gardiner Road will eclipse this one.”
Fortunately, funding will be available thanks to the passage of the Great American Outdoors Act. The act, which allocated funding to address the maintenance backlog in the national parks, funded the construction of the Yellowstone River Bridge and will help cover the costs of the Mammoth-Gardiner Road once construction begins.
“We couldn't do it without the funding we received,” Rhodes said. “It comes from different sources on every project, and sometimes it’s a combination of funding sources. It’s exciting work, and we’re very fortunate to be able to fund these big projects in Yellowstone.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
