Preliminary planning for the river crossing began in 1960 as part of Interstate 40 alignment studies for the Memphis - Little Rock corridor, which was constructed in segments between 1963 and 1968. Before the Hernando de Soto Bridge was completed, traffic going across the river was carried across the Mississippi River by the Interstate 55/US Highway 64/70/79/61 Memphis & Arkansas Bridge crossing, located southwest. Construction of the Hernando de Soto Bridge began in May 1967. The double-arch bridge was opened to automobile traffic on August 2, 1973. It was seismically retrofitted in 2006. The bridge is named for 16th century Spanish explorer Hernando de Soto who explored this stretch of the Mississippi River, and died south of Memphis.
Bridge illumination
At night, the bridge is illuminated by 200 sodium vapor lights along its "M" shape structure. The bridge was first illuminated on September 5, 1986, after $373,000 of private funds had been raised to fund the cost and installation of the lights. Due to some river traffic having issues with the lights at night reflecting on the water, the city installed a remote switch to toggle the lights on and off briefly while the vessel passes under the bridge. During the 2011 Mississippi River floods, the bridge became dark for about 2 months because the transformers that supply the electricity for the lights were removed to prevent damage to them by flood waters. The bridge was re-lit in a ceremony which occurred on June 21, 2011. It was announced after the opening of the Big River Crossing along the Harahan Bridge to the south that the existing sodium vapor lights along the Hernando Desoto Bridge would be replaced with a new LED lighting display, thus making the Hernando Desoto Bridge the second bridge over the Mississippi River to be lit as such after the Harahan. The new display can be lit in sync with the Harahan Bridge and display various color patterns dependent upon special occasions or requests. Both displays have been created under an initiative called "Mighty Lights." The $14 million privately funded project is expected to begin June 4 and be unveiled October 27, nearly exactly 2 years after the opening/initial illumination of the Big River Crossing.
Since 2000, the bridge has been under a seismic retrofitting project, allowing it to withstand a 7.7 magnitude earthquake, the similar magnitude of earthquakes during the 1811–12 New Madrid earthquakes. The retrofit project is also a means to protect the bridge as it is located within of the New Madrid Seismic Zone, serves as a major cargo route, and traffic thoroughfare across the river. Work is being completed as funds are available. As part of this project, the main span, approaches, and ramps for the downtown exit are being retrofitted. A bridge about west of the main span was rebuilt with earthquake considerations. As the main span is located entirely within Tennessee, the funding formula is split 60%/40% between TDOT and AHTD. To date, $175 million has been spent with another $80 million expected.
Incidents
On August 23, 2007, an inspector discovered that a bridge pier on the approach bridge west of the river had settled overnight, and the bridge was subsequently closed to perform a precautionary inspection. The bridge was reopened later that day.
