Interstate 75 in Georgia

Interstate 75 (I-75) in the US state of Georgia travels north–south along the U.S. Route 41 (US 41) corridor in the central part of the state, traveling through the cities of Valdosta, Macon, and Atlanta. It is also designated—but not signed—as State Route 401 (SR 401).

I-75 is the only Interstate to traverse the full length of the state from north to south, from the flat Atlantic Coastal Plains in southeast Georgia to the rolling mountains of North Georgia. In Downtown Atlanta, I-75 runs concurrently with I-85 as the Downtown Connector. The segment from SR 49 in Byron to I-16 in Macon is part of the Fall Line Freeway and may be incorporated into the eastern extension of I-14, which is currently entirely within Central Texas and is proposed to be extended to Augusta.

What would become the general routing of I-75 in Georgia was initially used by the western routing of the Dixie Highway beginning in 1916. Established in 1926, the Interstate's direct predecessor in Georgia is US 41, a national highway that has been largely supplanted in favor of the federally-funded freeway built under the Interstate Highway System—though limited-access elements of the Interstate existed as early as 1951.

With a length of 355.1 miles (571.5 km), I-75 is the longest Interstate Highway in Georgia. It enters the state near Valdosta, and it continues northward through the towns of Tifton and Cordele until it reaches the Macon area, where it intersects with I-16 eastbound toward Savannah. For northbound traffic, I-475 provides a relatively straight bypass west of that city and I-75's route.

After Macon, I-75 passes the small town of Forsyth. The freeway reaches no major junctions again until in the Atlanta metropolitan area. The first metropolitan freeway met is I-675, then followed by the Atlanta "Perimeter" bypass, I-285. It crosses inside the Perimeter and heads north several miles toward the Atlanta city center. I-75 then runs concurrently with I-85 due north over the Downtown Connector through the central business district of Atlanta. The two Interstates intersect I-20 in downtown. Several miles north of the I-20 interchange, the two Interstates split, I-75 heads in a general northwest direction while I-85 heads northeast, crossing outside the I-285 Perimeter and heading toward the major suburban city of Marietta. This section of I-75 just north of I-285 has 16 through lanes, making it the widest roadway anywhere in the Interstate Highway System. North of Marietta, the final major junction in the Atlanta metropolitan area is the I-575 spur. I-75 then traverses the hilly North Georgia terrain as it travels toward Chattanooga, Tennessee.

The 190-mile-long (310 km) section of I-75 from the northern I-475 intersection to the US 11/US 64 intersection in Ooltewah, Tennessee, is one of the longest continuous multi-state six-lane freeways in the US (some segments along this corridor have as many as 16 lanes).^{[citation needed]}

Due to recent lane widening in southern Georgia completed in 2011, the only four-lane section of I-75 in Georgia is bypassed by six-lane I-475; along this route, there are at least six lanes from the Alligator Alley portion of I-75 in Naples, Florida, to a portion of I-75 in Ooltewah (except a four-lane overpass on I-475 over a railroad track in Macon).

I-75 is the only Interstate to traverse the full length of the state from north to south. The entire length of I-75 in Georgia is part of the National Highway System, a system of routes determined to be the most important for the nation's economy, mobility, and defense.