Originally, the southern terminus of US 27 was in Cincinnati, Ohio. In 1928, the route was extended south to Chattanooga, Tennessee, then to Tallahassee, Florida in 1934. In 1949, it was extended to its current terminus in Miami. At its northern end, US 27 originally terminated at Cheboygan, Michigan. In 1937, the route was extended concurrently with US 23 to Mackinaw City, where it ended at the Michigan State Auto Ferry Dock along with US 23 and US 31. After the completion of the Mackinac Bridge in 1957, US 27 was extended across the bridge to the current intersection of I-75 and US 2 near St. Ignace. In 1961, what became I-75 was completed, enabling the roadway to be designated as I-75. At the same time, US 27 was truncated to an interchange with I-75 six miles (10 km) south of Grayling. In 2002, the northern terminus was moved to its current location.
