Purgatoire River Bridge is a historic concrete-on-I-beam bridge in Las Animas County, Colorado. Built in 1938, the bridge carries SH 12 over the Middle Fork of the Purgatoire River and reflects the influence of Works Progress Administration bridge construction in southern Colorado. It has been determined eligible for the National Register of Historic Places and is one of the preservation-priority bridges identified through the Historic Bridges of Colorado effort.
The bridge was constructed during the Great Depression, when federal work-relief programs helped fund and build public infrastructure across the United States. The Works Progress Administration, commonly known as the WPA, supported thousands of projects intended to create employment while improving roads, bridges, public buildings, parks, and other civic resources. In Colorado, WPA bridge projects often combined practical transportation improvements with Rustic-style design features.
Purgatoire River Bridge is significant under National Register Criterion A in the area of Government for its association with the WPA. The bridge represents a Depression-era public works investment in rural transportation infrastructure and reflects how federal programs shaped Colorado’s roads and bridges during the 1930s. These projects were not only engineering improvements; they were also part of a national response to economic crisis.
The bridge is also significant under Criterion C in the area of Engineering. CDOT identifies Purgatoire River Bridge as important because it displays a combination of standard Colorado Highway Department features and Rustic design characteristics associated with WPA bridge work. Its steel I-beam superstructure is especially notable because CDOT describes it as unusual for a WPA-built bridge in Colorado.
A concrete-on-I-beam bridge uses steel I-beams to support the roadway deck, with concrete components providing the driving surface and associated structural or protective elements. This type of bridge could be practical and durable, especially for rural highway crossings. At Purgatoire River Bridge, the steel I-beam structure is combined with stone masonry abutments and wingwalls, giving the bridge both engineering and architectural interest.
The bridge’s character-defining features include its steel I-beam stringer superstructure, stone masonry abutments, and stone masonry wingwalls. Its original doghouse-style concrete railings represent a standard Colorado Highway Department design and contribute to the bridge’s historic visual character. Together, these features help communicate the bridge’s period of construction, engineering function, and WPA-era design influence.
Purgatoire River Bridge is part of a broader group of historic bridges and culverts along SH 12 in Las Animas County. This corridor includes several WPA-era resources that demonstrate the importance of public works construction in improving rural mountain and foothill highways. Within this context, Purgatoire River Bridge stands out because of its unusual steel I-beam superstructure and its combination of standardized highway design with Rustic stonework.
As part of the Historic Bridges of Colorado preservation effort, the Purgatoire River Bridge has been identified as a preservation-priority bridge. CDOT selected the bridge for Group B, recommending development of an individual bridge management plan because it represents a significant trend in bridge building and is considered a notable example of its type. This designation recognizes the bridge’s importance within Colorado’s WPA-era transportation infrastructure.
Preserving Purgatoire River Bridge requires attention to its steel, concrete, and stone elements. Its long-term care may involve maintenance of the steel I-beam superstructure, repair of masonry abutments and wingwalls, treatment of original railings, and consideration of roadway safety needs. Because the bridge remains part of an active highway, preservation planning must balance continued transportation use with protection of historic character.
Purgatoire River Bridge helps tell an important story about Depression-era infrastructure in Colorado. It shows how federal work-relief programs, state highway design, and local transportation needs came together in a single bridge. Its materials and design reflect both practical engineering and the visual character often associated with WPA public works.
The continued preservation of Purgatoire River Bridge ensures that this chapter of Colorado’s transportation history remains visible along SH 12. The bridge is more than a crossing over the Purgatoire River; it is a reminder of how public investment, engineering adaptation, and rural highway development shaped Colorado’s historic road network.
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.