Georgia State Route 400 (SR 400; commonly known as Georgia 400) is a freeway and state highway in the U.S. state of Georgia serving parts of Metro Atlanta. It is concurrent with U.S. Route 19 (US 19) from exit 4 (Interstate 285) until its northern terminus south-southeast of Dahlonega, linking the city of Atlanta to its north-central suburbs and exurbs. SR 400 travels from the Lindbergh neighborhood in the Buckhead district of Atlanta, at Interstate 85 (I-85), to just south-southeast of Dahlonega. Like the Interstate highways, it is a limited-access road (with interchanges instead of intersections), but unlike the interstates (which were renumbered by GDOT in 2000), the exit numbers are not mileage-based, they are sequential. Once SR 400 passes exit 17 (SR 306), it changes from a limited-a