There was an appeal in 1928 to replace the closed down Ash Street Bridge in Tempe, Arizona. The State Highway Commission’s solution was the creation of the Mill Avenue Bridge. The first Mill Avenue Bridge (also referred to as the Old Mill Avenue Bridge) was designed by the Arizona Highway Department in 1929, it was completed and opened to traffic in the summer of 1931, and it was officially dedicated about two years later on May 1, 1933. The dedication celebration lasted for two days and one of the more notable persons in attendance was Arizona Governor and Tempe physician B. B. Moeur. The Mill Avenue Bridge in Tempe is the second oldest vehicle crossing on the Salt River and is considered one of the oldest crossings in the Phoenix area. It was originally named the ‘Tempe Bridge’ before it was renamed the Mill Avenue Bridge. When the bridge was first created it carried the title of the largest bridge in the State of Arizona. The Mill Avenue Bridge crossed over the Salt River almost in the exact same spot that Hayden’s Ferry had crossed the river nearly 60 years earlier.
The Mill Avenue Bridge was the only north-south route in Arizona prior to the construction of freeways in the 1950's and it was the main passage link for three major transcontinental highways: U.S. 60, U.S. 70, and U.S. 80. Roughly 8,000 vehicles used the bridge each day when it first opened to traffic in the 1930’s and during that time there were approximately eight rest stations along the bridge. For a long time the Mill Avenue Bridge took on the responsibility of being the only road that crossed the Salt River. In the 1930’s the Mill Avenue Bridge costed roughly $500,000 to construct (much cheaper than the second one which came about 60 years later.) The bridge is fully anchored to bedrock and has ten arched spans which are spaced 140 feet apart. A huge problem with the Salt River has been its tendency to flood, however, the Mill Avenue Bridge has proved itself time and time again as resilient against the harsh flooding. Often times during strong monsoon storms that rage throughout the Valley, the Mill Avenue Bridge is one of the very few bridges that remain open due to its structurally sound design and construction.
As the City of Tempe grew in size, traffic across the Salt River became heavier; this became too much of a burden for just one bridge. A second Mill Avenue Bridge, costing 8.8 million dollars, started construction in February of 1992 and was finally completed and dedicated two years later on February 26, 1994. The construction of this second bridge took a little bit longer than expected because there were some complications which delayed its construction. In January of 1993 severe flooding in Tempe destroyed the scaffolding used to construct the bridge and parts of the bridge itself were damaged as well.
The first and original (Old) Mill Avenue Bridge is a designated historical structure, as it has been listed on the Tempe Historic Property Register since November 4, 1999. Just three days later, on November 7, 1999, the official dedication to the Tempe Town Lake would take place. The two Mill Avenue Bridges no longer passed over a dry bed of desolate desert, but now a vibrant Town Lake. The Tempe Town Lake became instantly popular and really put Tempe on the map; completely revitalizing downtown Tempe. The Mill Avenue Bridge, which is a continuation of Mill Avenue, is likely named after the Hayden Flour Mill which has been a significant landmark in Tempe for close to 150 years.