State Route 9 (SR 9) is a north–south highway running from Atlanta to just north of Dahlonega, in the US state of Georgia. It is concurrent with U.S. Route 19 (US 19) from along 14th Street, in northwest Atlanta, to Roswell Road at Interstate 285 (I-285), in Sandy Springs. It is also concurrent with US 19 from Dahlonega to its northern terminus at US 129.

SR 9 parallels US 19/SR 400 for much its length. Because of its proximity to US 19/SR 400, it is a viable alternate to the congested "Alpharetta Autobahn." Along its route, the state road travels through the cities of Atlanta, Sandy Springs, Roswell, Alpharetta, Cumming, Dawsonville, and Dahlonega.

SR 9 originates at the intersection of US 19 (14th Street N.W.) and US 41 (Northside Drive) in Atlanta. It runs east–west from its origin to the intersection with West Peachtree Street N.W., and turns north here, shortly after crossing over I-75. SR 9 is signed as Peachtree Street N.W. from just south of I-85, and crosses under I-85 just north of the I-75/I-85 interchange north of Downtown Atlanta. Just south of Piedmont Hospital, SR 9 changes names from Peachtree Street N.W. to Peachtree Road N.W.

Starting at its intersection with SR 141, which originates here, SR 9 is signed as Roswell Road N.W. The route continues to run generally north, crossing I-285 at exit 25. From its origin to this point, SR 9 also overlaps with US 19, but continues north on its own from this point. It also largely parallels SR 400 from here.

Continuing north, SR 9 crosses the Chattahoochee River,and has reversible lanes up to its intersection with SR 120. The two roads are concurrent from here to its intersection with Old Milton Parkway,SR 9 is interchangeably signed as Atlanta Street or Alpharetta Street on this stretch, and as Alpharetta Highway from downtown Roswell and crosses State routes 92 and 140 and passes North fulton Regional Hospital. From downtown Alpharetta, it is interchangeably signed as Cumming Highway, Atlanta Highway, or Atlanta Road. Near exit 14 of SR 400, SR 9 starts to overlap with SR 20, until they split again in downtown Cumming.

From here, SR 9 is signed as Dahlonega Highway, and overlaps with SR 306 to Keith Bridge Road. It continues to run north on its own through Dawsonville, and then runs concurrent with SR 52 from their intersection to just north of Dahlonega. From here, it is again concurrent with US 19/SR 60, until SR 60 splits off near Porter Springs. SR 9 continues alongside US 19 until its terminus at the intersection with US 129 at Turners Corner.

In the past, US 19 followed the exact path of SR 9, but after the completion of SR 400, US 19 was moved to follow the path of I-285, then SR 400 to its end near SR 9 in Dahlonega. Due to the transport of moonshine from the mountains of North Georgia to Atlanta, SR 9 was called Thunder Highway.