State Route 400 (always known locally as Georgia 400 or just 400) is a highway in the U.S. state of Georgia, concurrent with U.S. 19 from exit 4B until its terminus just south of Dahlonega. Georgia 400 goes from Atlanta, at I-85, to Buckhea, Sandy Springs, Roswell, Alpharetta, Cumming, Dawson County, and Dahlonega. Like the interstate highways, it is a limited access road (with exit ramps instead of intersections), but unlike the interstates (which were renumbered by the GDOT in 2000), the exit numbers do not indicate mileage: they still go up sequentially one-by-one. Once 400 passes exit 17 (S.R. 306), it changes from a limited access highway into an at-grade divided highway.