Keith Bridge Road and Sawnee Drive, joined by an overlap with GA 9, makes up GA 306. This route, located in Forsyth County, serves as a cutoff between GA 20 west of Cumming to GA 53. Despite the less than obvious importance, GA 306 has high traffic volumes largely due to the growth of the county with tremendous traffic backups between GA 400 and GA 369.

In mileage, the Sawnee Drive section is 1.6 miles long, and the overlap with GA 9 is 2.2 miles long. The Keith Bridge Road section is the longest at 9.1 miles. A proposed new route extending west from Keith Bridge Road where it meets GA 9 is proposed that will end to the west at GA 20 where Spot Road currently joins the highway. This will likely result in the relocation of GA 306 to this new route in lieu of Sawnee Drive.

GA 306 first became a route in 1956-1957. The original highway was fully paved and only consisted of the longer portion along Keith Bridge Road. Keith Bridge Road is a historic local route to Gainesville that was partially submerged when Lake Lanier was filled the same time GA 306 became a state route. The highway was not extended to its full length until, though, until 1962 when the Sawnee Drive portion was added. Originally unpaved, the Sawnee Drive portion was fully paved by 1964.

The area along GA 306 has experienced heavy growth, especially along Sawnee Drive, so various improvements have been made along that section. The only other major work consisted of an interchange with GA 400 that opened to traffic in 1980. The GA 306 interchange holds the distinction as the last full interchange on GA 400 before the access control ends and the highway goes to at-grade intersections. No changes have occured to GA 306 otherwise since that time.