Ciénega Bridge

In 1920, the Arizona Highway Department began construction on a new bridge over Ciénega Canyon near the Pima/Cochise County Line to serve as a crossing for a number of transcontinental roads - notably the Bankhead Highway ("Broadway of America"), Dixie Overland Highway, and Old Spanish Trail. State engineers led by architect Merrill Butler designed a 146-foot long open-spandrel concrete arch bridge, with an additional span to cross the Southern Pacific Railroad's mainline, which runs through the canyon, bringing the total length to 278 feet. Once the design was complete, the Highway Department contracted the Tucson-based firm English & Pierce for construction, with supplies provided by the Highway Department. Following a dispute over cost exceeding what was stated in the contract, the Highway Department ultimately took over construction and the bridge was completed in March 1921 at a cost of $40,000.

In 1926, U.S. Route 80 was created and routed across the Ciénega Bridge and traffic increased. The stretch of the road gained a reputation for being dangerous, and from 1952-55 there were eleven deaths due to accidents on the bridge. As a result, a new, straighter alignment of US-80 was built to the south and completed April 9, 1955 and the Ciénega Bridge was transferred to Pima County (the new alignment of US-80 later became the route of Interstate 10). The bridge was finally added to the National Register of Historic Places on September 30, 1988. Other than having its guardrails replaced in 1989, the bridge remains exactly as it was built 100 years ago.