1920s 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. At this time,
SR 34 was established from
Carrollton to
Villa Rica. By the end of September 1921,
SR 16 was established from the Alabama state line to Carrollton. 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. US 29 was designated on SR 8 from Atlanta to the South Carolina state line. SR 16 from Alabama and Carrollton and SR 34 from Carrollton to Villa Rica were redesignated as a southern branch of SR 8. 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. Four segments had a "completed hard surface": from northwest of Atlanta to Decatur, the eastern two-thirds of the Gwinnett County portion of the Decatur–Lawrenceville segment, from northwest of
Watkinsville to the northeast part of Athens, and the eastern part of the Royston–Hartwell segment. By October 1929, US 19 was designated on the Atlanta–Lawrenceville segment. The Decatur–Lawrenceville segment had a completed hard surface.
1930s By the middle of 1930, US 78 was split into two
divided U.S. Routes:
US 78N was designated on the original path of SR 8 from Alabama to Villa Rica, and
US 78S was designated on the southern branch of SR 8. Later that year, the Austell–Atlanta segment, as well as the entire Clarke County segment, had a completed hard surface. By the beginning of 1932, four segments were also completed: the entire Carrollton–Villa Rica segment (except for its eastern end), from west-southwest of Douglasville to Austell, the Lawrenceville–Athens segment, and from the Madison–Franklin county line to the South Carolina state line. In February 1932, US 19 was shifted off of SR 8 to the north; US 23 was designated on the Atlanta–Lawrenceville segment instead. The eastern part of the Carrollton–Villa Rica segment of US 78S and the southern branch of SR 8 had a completed hard surface. Between May and August, the Villa Rica–Douglasville segment was completed. In August, two segments were completed: the Athens–Danielsville segment and a segment just south of the Madison–Franklin county line. Between November 1932 and May 1933, two segments were completed: the Bremen–Villa Rica and Danielsville–Royston segments. In May, the entire Alabama–Bremen segment (except for the western end) was also completed. The next month, the western terminus was also completed. 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. About two years later, the segment of the southern branch from the Alabama state line to Carrollton was completed. In 1938, US 78S was redesignated as
US 78 Alt., and US 78N was redesignated as the mainline US 78. By the middle of 1939, US 23 was shifted off of SR 8, to the north.
1940s and 1950s In 1942, the southern branch of SR 8 from Hartwell to the South Carolina state line was
decommissioned. Between November 1946 and February 1948, the southern branch of SR 8 from Alabama to Villa Rica was redesignated as
SR 8 Alt. 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. In 1952, US 78 Alt., as well as the northern branch of US 29, was decommissioned. The next year, the northern branch of US 29 was reinstated. Between September 1953 and June 1954, the original branch of US 29 in the Decatur area was redesignated as
US 29 Bus. By June 1955, US 278 was designated on SR 8 from Austell to southeast of
Avondale Estates.
1960s Between the beginning of 1956 and the beginning of 1961, US 29's path between Hartwell to the South Carolina state line was shifted southeast, off of SR 8 and onto
SR 181; the formation of
Lake Hartwell truncated SR 8. Between June 1960 and June 1963, a bypass of the northern part of Athens, designated as
SR 350, was established and paved as a divided highway from US 129/SR 15 in the north-central part of the city to US 29/SR 8 in the northeastern part. By the beginning of 1966, SR 8 was routed on US 29 Bus. in the Decatur area. SR 350 was upgraded to a freeway. It was under construction on a path southwest to US 29/US 78/SR 8/SR 10 in the western part of the city. US 29 was shifted northward, onto SR 350, from the
US 29 Temp./US 129/
US 441 Temp./SR 15 interchange to the Madison Avenue interchange. US 441 Temp. was designated on SR 350 from the US 29 Temp./US 129/US 441 Temp./SR 15 interchange to the US 441/SR 15 Alt. interchange. US 29/US 78/SR 8/SR 10 entered
downtown Athens on Broad Street. At Milledge Avenue, US 29 temporarily ended, and US 29 Temp./US 129/US 441 Temp./SR 15 traveled to the north-northwest. At Pulaski Street, SR 8 split off US 78/SR 10 to the north-northwest. At Dougherty Street, it intersected the southern terminus of
SR 15 Conn. and traveled east-northeast to SR 15 Alt. (Thomas Street). SR 8/SR 15 Alt. traveled concurrently to the north-northwest and curved to the north-northeast on Madison Avenue. SR 15 Alt. split off at Hobson Avenue, and SR 8 continued to its interchange with US 29/SR 350. In 1966, SR 350 was decommissioned. US 29/SR 8 was shifted northwest, onto the western part of the freeway. The former path through downtown, on US 78/SR 10, was redesignated as
SR 8 Bus. US 29 Temp. was decommissioned. The freeway was extended eastward one exit. SR 8 was extended on this freeway to the new exit and resumed its northeastern path. SR 106 was extended on US 29 to the Athens freeway, at the US 29/SR 8/SR 8 Bus. interchange. The next year, US 29 and SR 72 were both shifted onto the new path of SR 8 in the northeastern part of Athens to the freeway.
1970s and 1980s In 1976, SR 72 was proposed to be extended south-southeast and then south-southwest to US 78/SR 10 in the southeast part of Athens and then southwest and west-southwest to US 129/US 441/SR 15 in the southern part of the city. The next year, SR 8 east-northeast of Hartwell was shifted southeast, onto US 29/SR 181. Its former path was redesignated as
SR 8 Spur. 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. The next year, the eastern part of the freeway, north of US 78/SR 10, was downgraded to a divided highway. In 1983, the southwestern part of the freeway, designated as
SR 732, was proposed to connect both ends of it. In 1985, US 29 Bus. in the Decatur area was decommissioned, with SR 8 shifted northwest, onto the US 29 mainline. US 441 Temp. in Athens was decommissioned. SR 72's western terminus was truncated to its current location in the far northeastern part of Athens. In 1987, the Athens freeway was completed, with SR 10 on the southern part; its former path through downtown was redesignated as SR 10 Bus. SR 72 was re-extended to the freeway's northeastern interchange. The next year, SR 10 was shifted off of the Athens freeway through downtown, replacing SR 10 Bus. The entire freeway was designated as SR 10 Loop. US 78 was shifted from downtown to the southern part of the freeway; its former path became US 78 Bus. 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.
1990s and 2000s 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. The next year, SR 817's path from west-southwest of Dacula to SR 11 north of
Bethlehem was completed as an eastern extension of SR 316. In the Athens area, the paths of SR 15 and SR 15 Alt. were swapped. In 1993, SR 817's path from north of Bethlehem to US 78/SR 10 southeast of Bogart was also completed as an eastern extension of SR 316, with US 29 shifted onto the entire length. SR 8 was shifted onto US 29/SR 316 from southeast of Russell to southeast of Bogart. In 1995, US 29/SR 8 was shifted to southern part of the Athens freeway. SR 72 was again truncated to its current western terminus. The next year, SR 817's path in the southwestern part of Athens was completed as an eastern extension of SR 316, with US 29/US 78/SR 8 concurrent with it. In 2001, US 129/US 441/SR 15 was shifted onto the freeway, in the south-central part of its path, for a concurrency with the freeway for less than . They split off onto Macon Highway. The next year, US 129/US 441/SR 15 was shifted off of Macon Highway and onto the Athens freeway. In 2004, the
unsigned state highway designation
SR 422 was applied to the freeway. ==Major intersections==