Interstate 440 (I-440) is an east–west auxiliary Interstate Highway that runs through Nashville, Tennessee. It serves as a southern bypass around downtown Nashville, and is located on average about three miles (4.8 km) from the center of the city. I-440 is also known locally as the Four-Forty Parkway, and is designated as the Debra K. Johnson Memorial Parkway. At a length of 7.64 miles (12.30 km), I-440 runs between I-40 and I-24, and connects to I-65 and multiple U.S. Routes. Combined, I-440 and Briley Parkway, a controlled-access segment of State Route 155 (SR 155), form a noncontiguous inner beltway around downtown Nashville.

Originally proposed in the 1950s, I-440 was the subject of much controversy related to its location and design, which resulted in multiple design changes and delayed the highway's completion for many years. As a result, it was the last segment of Interstate Highway planned for Tennessee by the Federal-Aid Highway Act of 1956 to be constructed. After its completion in 1987, I-440 developed unforeseen congestion, safety, and surface issues, which prompted a reconstruction of the entire route that was completed in 2020.

The majority of I-440 is located below the level of adjoining streets and roads in an artificially-cut gulch. It contains three through lanes in each direction for its entire length, as well as auxiliary lanes in many locations. In 2024, annual average daily traffic (AADT) volumes on the Interstate ranged from 85,543 vehicles per day at the Murphy Road interchange to 117,968 vehicles per day directly west of the interchange with I-65.

I-440 begins west of downtown Nashville at a directional T interchange with I-40 south of Tennessee State University and heads directly south. It immediately crosses a CSX railroad mainline and U.S. Route 70 (US 70, Charlotte Pike), but does not have an interchange with this route. About 1.5 miles (2.4 km) later, the Interstate turns southeast and reaches a partial cloverleaf interchange (parclo) with US 70S (West End Avenue), which is indirectly accessible from the eastbound lanes via a connector road. Turning further southeast and passing near Centennial Park and Vanderbilt University, the highway has a parclo interchange with US 431 (21st Avenue, South Hillsboro Pike) some distance beyond. I-440 then turns directly east and reaches I-65 south of downtown Nashville about two miles (3.2 km) later in the top level of a symmetrical four-level "Spaghetti Junction" stack interchange, which includes four flyover ramps. It also crosses another CSX line and US 31 (Franklin Pike) at this location, but this route is not accessible. Briefly entering the city of Berry Hill, the Interstate turns east-northeast and meets US 31A/US 41A (Nolensville Pike) about 1.5 miles (2.4 km) later at a final parclo interchange where it also passes under another CSX line. A short distance later, the freeway crosses a fourth and final CSX mainline and reaches its eastern terminus at a directional T interchange with I-24, west of the Nashville International Airport and about one mile (1.6 km) south of the eastern end of a concurrency between I-24 and I-40. As a result of this, I-440 westbound is directly accessible at this interchange from I-40 westbound, and US 41/70S (Murfreesboro Road) is directly accessible from the ramp that carries I-440 eastbound traffic to I-24 westbound.

The route that is now Interstate 440 had its origins in 1955, when the Interstate Highway System was being planned. The highway was approved by the Bureau of Public Roads (BPR), the predecessor to the Federal Highway Administration (FHWA), on August 24, 1956, and was initially referred to as Segment #516. After the passage of the Federal-Aid Highway Act of 1956, which initiated the Interstate system, a public meeting was held on May 15, 1957, that identified proposed Interstate Highways and bypass routes around Nashville, including what would become I-440. The route numbering was approved by the American Association of State Highway Officials on November 12, 1958. The Tennessee Department of Highways, the predecessor to the Tennessee Department of Transportation (TDOT), was first authorized to begin studies related to right-of-way acquisition on July 12, 1961, by the BPR, and preliminary engineering work began in 1964. Planners chose to construct the route through both residential neighborhoods and in the location of a portion of the Tennessee Central Railway. The highway department was authorized to make right-of-way acquisitions for the section located between I-65 and I-24 on December 4, 1968, and the section between I-40 and I-65 on August 17, 1970.

The project experienced many setbacks and was subject to much controversy. After the National Environmental Policy Act (NEPA) became law in 1970, the FHWA determined in January 1971 that the I-440 project did not require an environmental impact statement, since it was already in the right-of-way acquisition phase, and gave final approval of the project's design. A lawsuit was filed by the National Wildlife Federation in 1973, which resulted in the requirement of an environmental impact study for I-440. The draft environmental impact statement was completed in 1978, and was approved by the FHWA on June 19 of that year. Approval of the final environmental impact statement occurred on September 19, 1980, and on February 20, 1981, TDOT was approved to begin advertising bids for construction of I-440.

The construction of I-440 required the demolition of many houses, and many Nashville residents opposed the project. Throughout the 1970s, many groups campaigned to stop the construction of the highway. Many residents of the areas near I-440 wanted TDOT to choose an alternative, such as constructing the route further to the south, widening existing surface streets, or adding more public transportation. However, traffic studies determined that the highway was necessary to relieve congestion on I-40. On December 9, 1980, a group of community activists known as the "Nashvillians Against I-440" filed a lawsuit, which named then-U.S. Secretary of Transportation Andrew L. Lewis Jr. as the defendant, in the U.S. District Court for the Middle District of Tennessee hoping to stop construction of the Interstate. The lawsuit was dismissed on September 23, 1981, when a judge ruled that the project would not adversely affect the natural environment and that TDOT had followed all necessary procedures.

Construction began in early 1982. The project required the removal of hundreds of thousands of cubic feet of dirt and rock. Initially, I-440 was going to be at-grade, but TDOT engineers chose to build it below the surface of the ground to reduce noise and vehicle emissions pollution after citizens in large cities living near Interstates had complained of disturbances caused by highway traffic. The state also agreed to take measures to reduce the impact of the Interstate as a further compromise to opposition by such means as designing the route as a parkway. This included separating the lanes by a narrow grassy median, which unintentionally made the route susceptible to crossover crashes, and curbed inner edges. Engineers chose to construct the highway with concrete rather than asphalt so it would last longer. Most of I-440 contained three lanes in each direction, except through the interchanges with Murphy Road, US 70S, US 431, and I-65, where it contained two lanes in each direction, with the third lanes functioning as auxiliary lanes in most places. A proposed interchange at Granny White Pike, which TDOT had acquired the right-of-way for, was abandoned in an effort to prevent the disruption of traffic patterns on nearby surface streets. The discovery of hairline cracks in multiple overpasses and ramps in the spring of 1985, which were repaired with epoxy cement, delayed the opening of I-440 by approximately eight months.