Interstate 75 (I-75) is a part of the Interstate Highway System that runs 1,786.47 miles (2,875.04 km) from Miami Lakes, Florida to the Canada–United States border at Sault Ste. Marie, Michigan. In the U.S. state of Kentucky, I-75 runs through the eastern half of the state, from the Tennessee state line near the city of Williamsburg to the Ohio state line near Covington. The Interstate serves the state's second-most populous city, Lexington. Outside of it, the route is mostly rural or suburban in nature, mainly providing access to other cities via state and U.S. Highways. The major landscapes traversed by I-75 include the rolling hills and mountains of the Cumberland Plateau, the flat Bluegrass region, the urban core of Lexington, and the highly urbanized suburbs of Northern Kentucky; it also very briefly crosses through the Eastern Kentucky Coalfield at its southernmost stretch and passes near the Daniel Boone National Forest in London.
Of the six states which I-75 passes through, the segment in Kentucky is the second-shortest, at 191.78 miles (308.64Â km) long. I-75 parallels the older U.S. Route 25 (US 25) and U.S. Route 25E (US 25E) corridors for its entire length in Kentucky. The Interstate was part of the Federal-Aid Highway Act of 1956, with a section of it from the Ohio River at Covington to an unknown location north of Richmond being the first segment of the Interstate Highway, opened in 1957. Unfinished portions of the highway were eventually completed in increments, with the very last section being opened in 1969. Due to the rapid growth and high traffic volume in the Lexington metropolitan area and Northern Kentucky, many widening projects and renovations have been undertaken on I-75 since then. The Interstate has one auxiliary route, I-275, a beltway encircling Cincinnati.