Interstate 75 (I-75): Route, Miles by State, Crashes and Tolls

How long is I-75?

The FHWA Route Log, as of January 2026, books 1,693.48 miles to I-75. Six Interstates have more: I-80, I-90, I-40, I-10, I-70 and I-95.

Wikipedia and Interstate Guide both put the road at 1,786.47 miles, and almost all of the 92.99-mile gap sits in Tennessee. The Route Log's Tennessee row lists 75.63 miles, while those sources give 161.86 for the stretch from East Ridge to the Kentucky line at Jellico. The table notes 19.60 miles near Knoxville that I-75 shares with I-40, but even with those added back, more than 60 miles are missing from the row. The other five state rows land within about 6 miles of the published figures.

Florida has the longest piece at 470.74 miles. Michigan follows with 395.35 and Georgia with 354.74.

Where I-75 starts and ends

I-75 begins at an interchange with SR 826, the Palmetto Expressway, and SR 924, the Gratigny Parkway, on the line between Hialeah and Miami Lakes. Local opposition stopped it a few miles short of I-95. The northern end is the port of entry for the International Bridge in Sault Ste. Marie, Michigan, which crosses into Ontario.

From Florida's southwest coast the road heads north through Tampa, Ocala and Gainesville, then Valdosta, Macon, Atlanta, Chattanooga, Knoxville, Lexington, Cincinnati, Dayton, Toledo, Detroit and Flint. North of Flint it crosses the Straits of Mackinac on the Mackinac Bridge to reach the Upper Peninsula.

Interstate junctions along I-75

The main Interstates on I-75 appear below from Florida north, beginning with I-4 and I-10 in Florida. I-40 is listed twice because the two routes run together into Knoxville, entering and leaving that shared stretch at separate interchanges. In Atlanta, I-85 joins for about 7.5 miles on the Downtown Connector, where I-20 crosses. The list ends with I-69 in Michigan; the long run north from that junction to the Canadian border meets no other main Interstate.

Fatal crashes on I-75

FARS counts 1,238 deaths in crashes on the I-75 mainline from 2020 through 2024, roughly 248 each year. Measured against the route's length, that comes to 13.9 deaths per 100 route miles a year, about one and a half times the network figure of 9.5. Nine of the 56 ranked Interstates have a higher rate. Yearly deaths held between 242 and 253 from 2020 to 2022, rose to 268 in 2023 and fell to 228 in 2024.

Florida and Georgia account for 793 of the deaths, close to two-thirds. Hillsborough County, around Tampa, had the most of any county with 68, then Fulton in Atlanta with 65, Broward with 48, and Cobb and Clayton in metro Atlanta. Georgia's 20.9 is the highest state rate. Tennessee's is 12.5, figured over the 161.86 miles other sources give for I-75 there, because its Route Log row of 75.63 miles is far shorter than the road. Michigan has the lowest rate on the route, 5.9.

Counties with the most I-75 crash deaths

Bridges on I-75

I-75's main line rides on 1,464 bridges in the 2025 National Bridge Inventory, and the median one dates to 1971. Twenty rate Poor, about 1 percent. Michigan holds 13 of them, from a state total of 260. Florida has the most bridges at 455, and Georgia's 233 include none in Poor condition.

The Brent Spence Bridge carries I-75 and I-71 over the Ohio River between Covington and Cincinnati. It opened in 1963 to handle 85,000 vehicles a day and was carrying about 150,000 by 2006. A truck crash and fire closed it on November 11, 2020, until December 22. Work on a companion bridge, backed by a $1.6 billion federal package, broke ground on May 8, 2026, and is expected to open to traffic in 2032. At the north end, the Mackinac Bridge has carried traffic across the straits since November 1, 1957, over a total length of 26,444 feet.

Tolls on I-75

As of January 2023, FHWA counts seven toll facilities on I-75, in Florida, Georgia and Michigan. A through trip pays on Alligator Alley, the 74.91-mile Everglades crossing from Andytown to East Naples, and again at the Mackinac Bridge. The International Bridge into Ontario is tolled as well. The remaining four are optional express lanes with free lanes beside them, two in Miami-Dade and Broward counties and Georgia's South Metro Express and Northwest Corridor lanes near Atlanta.

Each facility's miles in the table come from FHWA and can run past I-75 itself. The International Bridge entry, for one, counts approaches on both sides of the border. Oakland County, Michigan, added HOV lanes in October 2023 between 12 Mile Road and South Boulevard; they charge no toll and are reserved for carpools from 6 to 9 a.m. and 3 to 6 p.m.

I-75 auxiliary routes

I-75 has six three-digit routes. I-275 is the most scattered, with roads around Tampa Bay, in Knoxville and in Detroit, plus a Cincinnati beltway that crosses Kentucky, Ohio and Indiana. I-475 serves Macon, Toledo and Flint, and I-675 serves Atlanta, Dayton and Saginaw. I-575 runs 31.03 miles in metro Atlanta. I-175 and I-375 are spurs of little more than a mile in the Tampa-St. Petersburg area, and a second I-375, 1.15 miles long, serves Detroit, where MDOT plans to replace it with a surface boulevard.

How I-75 came together

I-75 was designated on August 14, 1957, and its first piece opened in 1962, between Lake City and Genoa in Florida. Michigan finished its section on November 1, 1973, and Tennessee on December 20, 1974. The road was complete from Tampa to Sault Ste. Marie on December 21, 1977, when the last Georgia link between Marietta and Cartersville opened.

The plan once ended the route in Tampa. Growth in Southwest Florida brought an extension, and by 1968 the federal government had agreed to pay 90 percent of it. I-75 moved to a bypass east of Tampa Bay, and the old route through the cities became I-275. The Miami-Dade and Broward section opened in 1986, and Alligator Alley, rebuilt with four lanes, took I-75 signs on November 25, 1992.

On December 11, 1990, fog on a stretch near the Hiwassee River in southeast Tennessee led to a 99-vehicle crash that killed 12 people. Farther north, the route reaches its highest point at more than 2,000 feet on Jellico Mountain, near the Kentucky line.

I-75 traffic and road conditions

The crash figures on this page end with 2024, so they cannot tell you why traffic stopped this morning. For current crashes, closures and work zones, check the state traveler information sites below.

I-75 questions