Interstate 275 (I-275), located in Florida, is a highway, 60 miles (97 km) long, serving the Tampa Bay Area. Its southern terminus is at Interstate 75 near Palmetto, where I-275 heads west towards the Sunshine Skyway Bridge crossing over Tampa Bay. From that point, I-275 passes through St. Petersburg before crossing Tampa Bay again on the Howard Frankland Bridge, then continues through the city of Tampa, where it connects to an interchange with Interstate 4 in Downtown Tampa. After the interchange, I-275 passes north through the Tampa suburbs to its northern terminus at Interstate 75 in Wesley Chapel.
Interstate 275 and its parent route Interstate 75 follow the opposite of the usual conventions of freeway routing. Normally, the parent route runs through a metropolitan area while an interstate with a three-digit number (beginning with an even number) serves as the bypass route. However, in this case I-275 runs through Tampa and St. Petersburg, while I-75 serves as the bypass route.
Interstate 275 begins at exit 228 of Interstate 75 with two lanes in either direction in rural Palmetto. 275 immediately heads west of its parent interstate and has an interchange US 41 2 miles (3.2 km) up the road. I-275's next interchange is with US 19, beginning a concurrency that lasts 13 miles (21 km). After this exit, I-275 reaches the Southern toll plaza for the Sunshine Skyway Bridge. There is a corresponding Northern toll plaza for southbound travelers. The Sunshine Skyway Bridge is a 4.1-mile-long (6.6 km) bridge that spans Tampa Bay. After reaching the northern end of the bridge, 275 enters St. Petersburg.
At the northern end of the bridge, drivers briefly drive on the left side as the freeway's lanes invert for about half a mile (about 1 km) before US 19 exits the freeway, serving as a local road in St. Petersburg. I-275 has multiple exits in the city, each of them serving the residential neighborhoods that the freeway passes through. At this point, the interstate widens to 3 lanes in either direction. 275's next major interchange is with Interstate 175, which provides access to Albert Whitted Airport and Tropicana Field, home of the Tampa Bay Rays. The next major interchange occurs less than a mile down the road with Interstate 375, providing access to the waterfront along Tampa Bay. After this exit, I-275 continues through residential neighborhoods until it passes beside Sawgrass Lake Park and then through an area of marshland. The freeway widens to four lanes in either direction before reaching its last interchange in St. Petersburg with SR 687. After traveling 19 miles (31 km) in St. Petersburg, I-275 crosses the Howard Frankland Bridge over Old Tampa Bay into Tampa.
I-275 has an interchange with SR 589, allowing access to Tampa International Airport. At this point, I-275 thins down to three lanes in either direction, and remains this way for the rest of the freeway. 275 then has an interchange with US 92, the first of two interchanges with the road, allowing access to downtown Tampa. 275 then crosses the Hillsborough River for the first time along its route. Afterwards, 6 miles (9.7 km) from its entry into Tampa, I-275 has its next major interchange with Interstate 4, a junction known locally as Malfunction Junction. This junction was always clogged with daily rush hour traffic and was subsequently overhauled. This interchange serves as I-4's western terminus, and allows access to Orlando and the east coast of Florida. After this major exit, 275 reaches an interchange with US 92 again, also allowing access to US 41. After this interchange, US 41 acts as the local road for the freeway for the rest of its route. 275 crosses the Hillsborough River a second time and enters residential neighborhoods within Tampa. 275 travels due north and parallel to US 41 for 4 miles (6.4 km) before turning northeast towards Interstate 75. At this point, 275 exits Tampa and enters Lutz, a suburb of Tampa. I-275 then reconnects with its parent interstate highway (I-75) and reaches its northern terminus.
I-275 originally opened in 1962 as a segment of I-75, from the present northern terminus to a diamond interchange at Bearss Avenue. The portion of Interstate 4 that would later become a part of I-275, the Howard Frankland Bridge, and its short freeway stubs at the bridge's endpoints, opened to traffic about a year earlier. In 1964, the stub of what was then known as I-4 between 50th St. (through "Malfunction Junction") and Armenia Avenue was completed. "Malfunction Junction's" northern end was a pair of ramp stubs that would later be filled in by I-75. In 1965, the segment of I-75 from "Malfunction Junction" to about Sligh Avenue was completed, and by 1967, the remaining gaps in I-4 and I-75 were filled and opened to traffic.