Yellowstone’s new 180-foot-tall, 1,285-foot-long bridge will open in 2025

The National Park Service had high hopes for replacing the Yellowstone River Bridge. As the park prepares to close most of its roads for the winter season, an important milestone is approaching.

Huge steel beams that will support tourist traffic across the Yellowstone River are being installed throughout the 1,285-foot-long space. This brings the project closer to its November 2026 goal, but traffic on the bridge will begin sooner.

“All the steel beams are in place,” Daniel Rhodes, a landscape architect with Facility Management and Operations in Yellowstone, told Cowboy State Daily. “Weather permitting, we hope to have everything ready by 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 already showing signs of age.

Rhoades said this is the largest project he has ever been involved with in Yellowstone.

“The Pelican Creek Viaduct that we built in 2020 is 1,500 feet long but only 17 feet high,” he said. “The existing bridge over the Yellowstone River is 604 feet long, and the new bridge is 1,285 feet long and is 180 feet above the river.”

This makes the new bridge comparable to the Gardiner River Bridge near North Entrance, which is 962 feet long and 201 feet above the river.

Yellowstone has not developed a project at this elevation since the 1930s, when the Gardner River Bridge was built. Rhoades said making the new bridge much higher would be a simpler, safer and less intrusive option for the critical road corridor.

“The pillars allow the bridge deck to reach 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 descends a steep slope on both approaches. The new design was made to maintain the level of ratings.”

The tall concrete columns were lifted in the summer with the help of cranes, such as can be seen during the construction of skyscrapers in New York or Denver. An aerial view of the construction site shows a much smoother flow through the expanse of the Yellowstone River Canyon.

Steel delivery

Now that the three concrete columns have reached the required height of 160 feet, massive steel beams are being installed across them. Rhodes said the beams are 9 to 15 feet high and 100 feet long.

“They are huge,” he said. “The steel beams are installed on top of the concrete supports, and then the concrete deck is installed on top of the beams on which the road will be built.”

The logistics of getting the beams to the construction site were complex. Rhodes said the route through the park needs to be carefully planned to ensure the steel beams can be moved safely without damaging any infrastructure.

“They entered through the West Entrance and then went up through Dunraven Pass,” he said. “A couple of bridges north of Madison Junction wouldn’t support that weight, so we moved them over Dunraven.”

Transport of the beams from West Yellowstone to the Tower Junction construction site was scheduled during low-traffic hours, typically early in the morning, to reduce traffic impacts. Trucks carrying 100-foot beams had to be carefully navigated along narrow, winding roads to reach their destinations.

“We coordinate an entire orchestra,” Rhodes said. “The park, the contractor and bridge engineers from the Federal Highway Administration worked together to determine the load rating of the bridge and developed a predetermined route. And they all did it.”

Supreme compromise

Rhoads believes the new bridge over the Yellowstone River will be a “great improvement” over the existing bridge. But as with every major park project, there were some compromises that would change the experience of crossing the Yellowstone River.

“It’s a constant battle between safety and what the public wants to see,” he said. “But what the public wants is always taken into account.”

One major 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 canyon appear more distant.

Rhodes said safety and reducing the bridge’s impact on the landscape were priorities in the design, so a taller bridge was preferred over the existing one. However, the new bridge has been designed to offer a similar experience to visitors and local wildlife.

Rhodes said the project is expanding the Yellowstone River picnic area. There will be a trail along the Yellowstone River Canyon, offering “excellent views” of the river and canyon, as well as walking paths on the bridge itself.

“There will be parking on both sides of the bridge and people will be able to walk on the deck if they want,” he said. “Safety barriers will be installed between the roadway and walkways to ensure maximum safety for the public as they walk along the deck.”

These protective barriers will be a welcome addition for the bison. The Yellowstone River Bridge is a popular migratory corridor for Yellowstone bison that they have reminded construction crews about many times.

“We had to have a lot of traffic delays just because the bison were on the bridge,” he said. “The old bridge is a great corridor for bison, and we expect that to continue with the new bridge.”

All 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 instrumental in the design and construction of the new Yellowstone River Bridge.

“Federal Highway Administration bridge engineers say their structures are designed to last 75 to 100 years under normal wear and tear,” he said. “Each bridge has undergone a lot of redesign for safety reasons, but current estimates are that this bridge will last at least that long.

This will be important when the new bridge opens to traffic. It will maintain a constant flow of traffic through the vital lifelines of the Cooke City and Silvergate communities during the busy winter seasons.

In addition to the new parking spaces, a new interchange is being built across from the Roosevelt Corral. It will be slightly closer to Tower Junction and will be connected to the existing north-east access road to facilitate travel and service.

“Everything was taken into account,” Rhodes said. “This road is open 12 months of the year, so the height of the bridge maintains the grade for safer winter travel.”

Discovery of the bridge and lost stream

The “Great Push” to complete the new Yellowstone River Bridge will begin next spring. Rhodes said the precast concrete deck panel will be placed on top of the steel beams, which will be covered by another layer of concrete to complete the bridge deck.

If all goes according to schedule, Rhodes hopes to open the bridge to traffic by the end of 2025. The only unfinished business will be the dismantling of the existing bridge, which will be completed by November 2026.

“We have to remove 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 supports will come down last.”

Removal of the 1939 bridge will allow for important landscape restoration. Rhodes said the final aspect of the $118 million project will be restoring the Lost Creek drainage.

“The Lost Creek drainage was damaged when the original road was built, and we are going to restore it to its natural functioning,” he said. “This will be an important part of the restoration as we remove the previous road corridor.”

On the Other Side

The Yellowstone River Bridge project is one of the most expensive construction projects in Yellowstone history. However, it already appears to be eclipsed and spent more than what Rhodes sees further down the road.

“We are currently designing a permanent Mammoth-Gardiner road,” he said. “It looks a little 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 project.”

Fortunately, funding will be available through the passage of the Great American Outdoors Act. The legislation, which provided funding to address the maintenance backlog in national parks, funded construction of the Yellowstone River Bridge and will help cover the costs of the Mammoth-Gardiner Road once construction begins.

“We couldn’t do this without the funding we received,” Rhodes said. “For each project, funding comes from different sources and sometimes from a combination of sources. This is exciting work and we are very fortunate to be able to fund these major projects in Yellowstone.”

Andrew Rossi can be contacted at [email protected].