The highway travels from its western terminus at US 78 and SR 4 at the Alabama state line west of Tallapoosa to its eastern terminus at US 29 at the South Carolina state line at the south end of Lake Hartwell.
SR 8 starts at the Alabama state line west of Tallapoosa in Haralson County, and closely parallels I-20 from there into Atlanta.
In Decatur, SR 8 turns northeast, crossing I-285 in Tucker, and paralleling I-85 through Lilburn and Lawrenceville in Gwinnett County to Auburn in Barrow County, where the highway turns southeast and heads into Winder.
The following portions of SR 8 are included as part of the National Highway System, a system of roadways important to the nation's economy, defense, and mobility: SR 8 was established at least as early as 1919 on its current path, except for the Lawrenceville–Athens segment going through Winder, and the segment from Hartwell to the South Carolina state line traveling to the east-northeast.
[2] By the end of September 1921, SR 16 was established from the Alabama state line to Carrollton.
[2][6] By October 1926, US 78 was designated on the path of SR 8 from the Alabama state line to Decatur and a segment west-southwest of Athens.
An unnumbered road was established from US 29/SR 8 in Hartwell east-southeast to the South Carolina state line, at a point just south-southeast of the current eastern terminus of SR 8.
The eastern part of the Carrollton–Villa Rica segment of US 78S and the southern branch of SR 8 had a completed hard surface.
[19][20] The next year, another southern branch of SR 8 was established from Hartwell to the South Carolina state line on the previously unnumbered road in the area.
The western terminus of the original southern branch had a completed hard surface.
[21][22] About two years later, the segment of the southern branch from the Alabama state line to Carrollton was completed.
[26][27] In 1942, the southern branch of SR 8 from Hartwell to the South Carolina state line was decommissioned.
US 29 in the Decatur area was split into two paths: the original was a direct path from Atlanta to Lawrenceville; the northern branch bypassed the city with SR 8 Spur; both branches were designated US 29.
[33][34] Between September 1953 and June 1954, the original branch of US 29 in the Decatur area was redesignated as US 29 Bus.
traveled concurrently to the north-northwest and curved to the north-northeast on Madison Avenue.
SR 8 was extended on this freeway to the new exit and resumed its northeastern path.
[45][46] In 1980, the freeway in Athens was completed on the eastern, southeastern, and southern parts of the city, with US 129/US 441/SR 15 designated on these segments.
[47][48] The next year, the eastern part of the freeway, north of US 78/SR 10, was downgraded to a divided highway.
[48][49] In 1983, the southwestern part of the freeway, designated as SR 732, was proposed to connect both ends of it.
SR 72's western terminus was truncated to its current location in the far northeastern part of Athens.
[54][55] In 1989, a southern bypass of the Dacula–Athens area, designated as SR 817, was proposed from US 29/SR 8/SR 316 west-southwest of Dacula to the southwest corner of the Athens freeway.
[55][56] In 1990, SR 181's western terminus was truncated to its current location, an intersection with US 29/SR 8 east-southeast of Hartwell, and off of US 29/SR 8.
was an alternate route of SR 8 that existed completely within Carroll County.
[2] By the end of September 1921, SR 16 was established from the Alabama state line to Carrollton.
[8][9] By the beginning of 1932, the entire Carrollton–Villa Rica segment (except for its eastern end) had a "completed hard surface".
[10][11] In February 1932, the eastern part of the Carrollton–Villa Rica segment of US 78S and the southern branch of SR 8 also had a completed hard surface.
Almost immediately, it intersects the southern terminus of Mirror Lake Boulevard.
[70][71] By 2013, the northern terminus of the connector route was shifted eastward on a curve.
Between the beginning of 1945 and November 1946, it was established on a northern branch of US 29 (Scott Boulevard) between two intersections with US 29/SR 8 west-southwest of the city and north-northeast of it.
was a business route of SR 8 that existed entirely within the city limits of Athens.