1920s The road that would later be designated as part of US 25 was established in 1920 as an unidentified road from Brunswick to about Sterling, SR 27 from that point to Jesup, SR 38 from Jesup to Ludowici, SR 23 from Statesboro to Millen, and SR 21 from Millen to Augusta. By the end of the next year, SR 23 was designated between Ludowici and Glennville, SR 26 was designated on a routing southwest of, and into, Statesboro, SR 46 was designated between Statesboro and Hopeulikit, and SR 67 was designated from Hopeulikit to a point southwest of Millen. The latter two supplanting SR 23, which was rerouted on a more westerly path. By the end of 1926, US 341 was designated along SR 27 between Brunswick and Jesup. By the end of 1929, US 80 had been designated along SR 46 between Statesboro and Hopeulikit.
1930s By 1932, US 341/SR 27 were paved in Glynn County. Also, SR 73 was designated from Clayton to an intersection with SR 26 southwest of Statesboro, approximately where I-16 is today. Farther to the north-northwest, US 25 was designated from Hopeulikit to Augusta, and US 25/SR 21 were paved from Waynesboro to Augusta. That January, the positions of SR 26 and SR 46 were swapped. In April, SR 23's Ludowici–
Darien segment was redesignated as part of SR 99; SR 23 was rerouted along SR 38 between Jesup and Ludowici. By May 1933, that Jesup–Ludowici segment of SR 23/SR 38 was paved. In May, US 25/SR 21 were paved from Millen to just north of the Jenkins–Burke county line. In July, SR 23 was paved from the Long–Tattnall county line to Glennville. In late 1934, SR 73 was extended southward from Claxton to Glennville. A vert short stretch of SR 46 south of Statesboro was paved. US 25/SR 67 was paved from just southeast of the SR 23 intersection south-southwest of Millen and into that town. Between June and October 1935, US 25/SR 21 was paved between the Jenkins–Burke county line and Waynesboro. At the end of that year, nearly half of US 341/SR 27, between the Glynn–Wayne county line and Jesup, was paved. In mid-to-late 1936, SR 46 was paved from the SR 73 intersection southwest of Statesboro into the city. About one year later, all of US 341/SR 27 between Brunswick and Jesup were paved. Also, a short stretch of SR 23 northwest of Ludowici was paved. In August 1938, all of SR 23 between Ludowici and Glennville was paved. By mid-1939, US 25 was designated along US 341/SR 27 between Sterling (and perhaps Brunswick) and Jesup. It was also designated along SR 23 between Ludowici and Glennville and along SR 73 between Claxton and the intersection with SR 46, southwest of Statesboro. It is unclear whether it was designated along the stretches of roadway in between those.
1940s Between April and July 1941, US 25/SR 73, between the Evans–Bulloch county line and the intersection with SR 46, were paved. In 1942, SR 73 was paved from Glennville to the Tattnall–Evans county line. In 1943, SR 73 was paved all the way from Glennville to Claxton. By the end of 1946, US 25 was designated along SR 23/SR 38 between Jesup and Ludowici. In Augusta, US 25 (and presumably SR 21) approached downtown on Savannah Road. It intersected US 1/US 78 (Milledgeville Road). The three highways traveled to the northeast on Twiggs Street until just past Gwinnett Street, where they curved to the north-northeast onto 7th Street. At the intersection with SR 28 (Broad Street), US 1/US 78 turned right, while US 25 turned left. At 13th Street, US 25 turned to the right and crossed into South Carolina. Also, all stretches of road from Brunswick to Augusta were paved. By the middle of 1948, US 301 was designated along US 25/SR 23 from Ludowici to Glennville.
1950s By the end of 1953, US 301 was designated along SR 73 between Glennville and Claxton. In 1955, US 278 was added to the intersection of US 1/US 78 and US 25 in Augusta. Also, US 1/US 78 left the concurrency with US 25 just past Gwinnett Street and turned right onto Calhoun Street, then left onto 8th Street. In 1956, the four U.S. Highways in Augusta were rerouted on a bypass to the east of the main part of downtown. The former route of US 78 became part of
SR 12, and the former route of US 1 became part of
SR 4. SR 4 also took the former route of US 25 through the city but ended at SR 28. US 25 followed the bypass onto 8th Street with US 1/US 78/US 278. At the intersection with SR 28, it turned left as it had done previously, just a little farther to the east-southeast. It appears that US 278 ended at this intersection. SR 21 followed Savannah Road and ended at the intersection with SR 4.
1960s By the middle of 1960, US 25 was no longer routed on Broad and 13th streets. It was rerouted to continue following US 1/US 78 and SR 10, which had only recently joined the concurrency. In its place was the newly commissioned US 25 Bus. Between 1960 and 1963, SR 121 was designated, concurrent with US 25, as it does today. At least as far back as 1965, US 25/US 341/SR 27 traveled through Brunswick on Norwich Street, before being moved slightly to the west. During this time period, the eastern bypass in Augusta was named Gordon Highway. SR 121's concurrent section was designated along US 25, as it exists today. The Gordon Highway–Broad Street intersection was reconfigured into an interchange.
1980s In the early part of the decade, SR 21's concurrency with US 25 was truncated at Millen. Between 1983 and 1986, US 25/US 341/SR 27 were moved to the west in Brunswick to follow Newcastle Street. ==Future==