Interstate 240 (abbreviated I-240) is an Interstate Highway in the U.S. state of Tennessee. Running 19.27 miles (31.01 km) or 31.0 km, it loops southward from Interstate 40 in east Memphis, then turning west at TN 385 (Bill Morris Parkway). At I-55, the highway turns north and runs through midtown to end at I-40. The section in East Memphis around Walnut Grove Road is the busiest interstate in Tennessee, with an AADT of just under 200,000 vehicles.

I-240 was first planned circa 1955, but it was to have been a 30.8-mile (49.6 km) or 49.6 km beltway to completely encircle midtown Memphis, with the exception of the segment between Interstates 40 and 55, which was proposed as Interstate 255. Later, that number was decommissioned in favor of I-240 running in a full loop, with I-40 running from downtown to east Memphis. However, in 1957 citizens collected 10,000 signatures protesting the route, which cut through Overton Park in midtown. The controversy lasted until the 1970s, when the Supreme Court ruled that the Overton Park route be canceled, shifting I-40 onto the northern leg of I-240. Part of the proposed I-40 route was already built—from N. Highland St. east to the I-40/240 junction. The road is now called Sam Cooper Boulevard, and is owned by the city.

In 2000, the City of Memphis built an extension to the former I-40 section of Sam Cooper Blvd. This extension runs west from N. Tillman St. (the former entry/end point for Sam Cooper Boulevard) as a limited access parkway to East Parkway N. (a former exit for the proposed "Overton Park route").

The interstates overlapped around the northern bypass of Memphis for many years, but I-240 signs were later removed from the northern leg for reasons of redundancy. (The exit numbers for I-240—the exception being exits 1A-1C, which were changed to 1E-1G—remain, causing redundancy on I-40 exits 1, 1A-G, 12, and 12A-C.)

It is unknown why, but few or no I-240 markers placed since the 1980s carry the state name (Tennessee).[citation needed]

On January 18, 2008, the Federal Highway Administration authorized the states of Mississippi and Tennessee to extend I-69 from the I-40/TN 300 interchange in north Memphis to the I-55/I-69 interchange in Hernando; however, Tennessee has not yet[update] signed the extension of the route, although Mississippi has already done so.

On March 24, 2010, a sinkhole formed in the two leftmost northbound lanes north of the Walnut Grove interchange. It was initially thought to have been a smaller pothole and had been paved over the day before. It formed around 3:00 in the afternoon and damaged several cars, although no injuries were reported. These two lanes were shut down until March 28 while the sinkhole was filled.

I-240 has seen much reconstruction over the past decade, as area growth has demanded increased capacity. Both interchanges with I-40 have been reconstructed (with further improvements coming to the East Memphis interchange in a few years) due to the amount of traffic taking I-40 through Memphis.

Starting April 2011, a widening project began on the stretch of I-240 from north of TN 385 to north of Walnut Grove Road. This is due to increased traffic volumes since the freeway's construction. This includes adding a lane to each side (which would make it an average of 4 lanes on each side), retaining walls, noise barriers, and redesigning the Poplar Avenue interchange: a main source of congestion. The project is expected to last until June 2013.

The exits on I-240 run clockwise from east to west, reflecting their initial numbering as part of a circumferential beltway.