It uses a blue state route designation because it is part of the Appalachian Development Highway System.

It is one of the Georgia Department of Transportation's Governor's Road Improvement Program (GRIP) corridors.

[1] SR 515 is a significant route for the north Georgia mountains, funneling tourist traffic and serving as a growth corridor.

SR 515 sees an Average Annual Daily Traffic (AADT) of more than 10,000 vehicles south of Blue Ridge, and at least 5,000 on the entirety of the route.

[5] The road that would eventually become numbered as SR 515 was established at least by 1919 along nearly the same alignment as it travels today.