The Plum Bush Creek Bridge is a historic concrete rigid frame bridge in Washington County that carries US 36 over Plum Bush Creek. Built in 1938, it is one of the preservation-priority bridges identified through the Historic Bridges of Colorado effort and is part of a small group of rural concrete rigid frame bridges associated with Colorado highway development on the eastern plains.
The bridge is significant for its engineering as a concrete rigid frame structure. In this bridge type, the deck and supporting elements are designed as a single reinforced-concrete frame. This differs from more conventional bridge forms in which the deck is structurally separate from the abutments or piers. The rigid frame design created a strong, durable, and compact bridge form that was useful for certain roadway crossings and represented the Colorado Highway Department’s experimentation with modern reinforced-concrete bridge technology.
The Plum Bush Creek Bridge was listed on the National Register of Historic Places in 2002 as part of the Highway Bridges in Colorado Multiple Property Submission. The bridge is significant under Criterion A in the area of Transportation for its association with the development of U.S. Highway 36 across Colorado’s eastern plains, and under Criterion C in the area of Engineering as a rare rural example of a concrete rigid frame bridge. Together with the nearby West Plum Bush Creek Bridge, it reflects the Colorado Highway Department’s late-1930s experimentation with rigid frame bridge design outside of Denver.
The Plum Bush Creek Bridge also reflects the development of US 36 as an important east-west transportation route. Highways across eastern Colorado served local agricultural travel, regional commerce, and longer-distance movement between the Front Range and communities beyond the state line. Bridges along these routes helped transform rural roads into more reliable state highways by replacing less durable crossings with engineered structures capable of supporting automobile and truck traffic.
Although the Plum Bush Creek Bridge is modest in scale, its significance comes from its design, integrity, and relationship to the larger highway corridor. Rural bridges like this one were part of the everyday infrastructure that made statewide transportation possible. They carried traffic across small but necessary crossings and helped standardize travel through rural areas that had previously depended on less permanent road improvements.
The character-defining features of the Plum Bush Creek Bridge include its concrete rigid frame superstructure and substructure, concrete abutments and wingwalls, and original bridge form. These features help communicate the bridge’s structural type and its late-1930s construction period. Its understated design reflects the functional priorities of state highway engineering while still retaining enough integrity to convey its historic character.
The Plum Bush Creek Bridge is especially important when considered alongside the nearby West Plum Bush Creek Bridge. Both were built in 1938, both carry US 36 in Washington County, and both represent concrete rigid frame construction in a rural plains setting. Together, they provide a paired example of how similar bridge designs were used across related drainage crossings as Colorado’s highway system expanded and improved.
As part of the Historic Bridges of Colorado preservation effort, the Plum Bush Creek Bridge has been identified by the Colorado Department of Transportation as a preservation-priority bridge. This status recognizes the bridge as a representative example of Colorado’s bridge-building history and as a candidate for long-term preservation planning.
Preserving the Plum Bush Creek Bridge helps tell a more complete story of Colorado’s historic transportation network. It broadens the focus beyond highly visible bridges in cities, mountain canyons, or large river corridors and highlights the infrastructure that supported travel across the eastern plains. Its continued preservation helps maintain the physical evidence of Colorado’s rural highway modernization during the twentieth century.
This bridge is one of the 23 preservation-priority bridges featured in Colorado Preservation, Inc.’s Historic Bridges of Colorado listing. View the full Historic Bridges of Colorado overview to learn more about the statewide preservation effort.