(Photo credits: New state highway bridge across the Gila River, showing Gillespie Dam, Arizona". Color printed postcard. Published by Harry Herz, Phoenix, Arizona. Printed by C. T. Co., Chicago. Number 119775. Number 222. Unused. Circa late 1920s. Gillespie Bridge. Highway 80 near Gila Bend, Arizona". Real photo postcard. Publisher not given. Number C-37. Unused. Circa 1940s).
The bridge, which was at the time the longest highway bridge in the state of Arizona, was immediately incorporated into the highway system as Route 80. The bridge carried US 80 traffic until 1956 when the highway was decommissioned, devolving to a county highway, thus placing the bridge under Maricopa County care. The bridge was added to the National Register of Historic Places on May 5, 1981  
Between 1921 and 1926, horse teams pulled automobiles across the apron of the dam. The dam was never meant to be a permanent solution and even before Gillespie finished his dam plans were underway to place a bridge near this location.
In 1925, the Arizona Highway Dept. began designing a structure to span the Gila River; construction began in January 1926. At 1660 feet, it was the largest steel structure in the state.

In 1911, 84 delegates from Arizona, New Mexico, and California met in Phoenix and formed the Ocean-to-Ocean Highway Association. Their goal was to create a route far enough south to allow year round travel between the Atlantic and Pacific Coasts. Other regions were competing for the creation of the nation's first transcontinental highway. While this association's route did not have as large of population centers which it would be linking, it did have climate in its favor. (Photo credit: Gillespie Bridge. Highway 80 near Gila Bend, Arizona". Real photo postcard. Publisher not given. Number C-37. Unused. Circa 1940s). 

A short drive north of Gila Bend up the "Old 80" highway is the historic Gillespie Dam. A rededication ceremony for the historic dam was held October 20, 2012 and the site now includes a visitor interpretive center.

Gillespie Dam