Filed Under Fallon

Yellowstone River Bridge

The Yellowstone River Bridge is the longest truss bridge built in Montana at 1,142 feet. It is also one of the few bridges built in Montana during World War II. During the 1930s, the Montana Highway Department welcomed an influx of New Deal money by embarking on ambitious road improvements, including building more than 1,000 bridges. After the attack on Pearl Harbor, however, bridge building screeched to a halt, except on roads designated as critical to national security. These included U.S. Highway 10, which connected Seattle to Minneapolis. Thus, in 1943, when an ice jam destroyed the bridge at Fallon, forcing motorists and critical war materials to make a 55-mile detour, the Secretary of Defense ordered the highway department to build a replacement. Specifically designed for wide river crossings, the steel and concrete bridge is a continuous span Warren through truss structure. The trusses are arranged in a “W” configuration that identifies them as Warren trusses. The highway department used this style of bridge from 1933 to 1946. Despite authorization from the War Production Board, labor and steel shortages slowed construction, as did high water and inclement weather. The W. P. Roscoe Company of Billings hired men from the Crow Reservation to help pour the concrete piers and subcontracted with another company to erect the steel trusses. To spectators’ amazement, crews worked high in the air, sauntering across I beams seventy feet above ground “as nonchalantly as if traveling on a broad highway.” The bridge opened to much fanfare in late November 1944.


Yellowstone River Bridge
Yellowstone River Bridge Yellowstone River Bridge. Interior view of the bridge on the Frontage Road near Interstate-94 (to the west of the bridge), facing north to northeast. Source: Montana State Historic Preservation Office Creator: Photographer unidentified Date: Date unknown


Milepost 1 on I-94 Frontage Road (Old US Highway 10), Fallon, Montana | Public


The Montana National Register Sign Program, “Yellowstone River Bridge,” Historic Montana, accessed July 25, 2024,