GA 331 first appeared in 1961 as a short connector between I-85 and Old Dixie Highway (U.S. 19/41 Business, now both mainlines). The original route was only two lanes and was then known as Thames Road, but was widenened to four lanes soon after commissioning. East of U.S. 19/41 Business, the road continued into Forest Park as a locally-maintained Georgia Avenue. At the time, GA 85 still had a full interchange at I-75 except for access to the route northbound, so that was not the major purpose of the road. In all, the road apparently was commissioned largely due to the State Farmers Market that had opened at that location shortly before the route was commissioned. As the Farmers Market caused sharply increased traffic due to the major draw for both tourists and overall commerce, the short state highway was needed to manage the heavy traffic between the two routes.

GA 331 as it was when it was first established in 1961. Note GA 160 to the east and the Farmers Market (1964 GHD Map).

In 1971, GA 331 was extended from the short 1.2 mile connector it had been previously to nearly three times its original length. The extended route, following what had been Georgia Avenue, was all completely renamed Forest Parkway. It was in those years that Clayton County was experiencing phenomenal growth as a second-wave suburb of Atlanta, and the area around Forest Park was booming. It was also this growth that led to a widening and reconstruction of I-75 at I-285 in 1976 that resulted in the closure of all but one ramp of the GA 85 interchange, increasing the importance of GA 331 as access to the major four-lane highway. The population explosion finally resulted in the four-laning of the entire length of GA 331, which was completed in 1980.

Extended GA 331 in 1973. Note how closely it parallels GA 160. The two roads are literally across the railroad from each other. Also note the GA 85 interchange with I-75, which is removed a couple years later (1973 GHD Map).

Another interesting attribute of the extension was that GA 331 was then running parallel with Main Street (GA 160) in Forest Park. The two routes ran so closely that they were in places right across the railroad tracks from each other. This arrangement eventually meant that one of the two routes would win out, and GA 331 had the advantage of interstate access, four lanes and a more direct connection to major destinations. As a result, GA 160 was decommissioned along Main Street by the early 1990's, leaving GA 331 as the sole route through downtown Forest Park.

GA 331 how it still is today. Note the severed ramps where GA 85 meets I-75. Also note the gray line denoting what was GA 160 through downtown Forest Park (1997 GDOT Map).

In more recent years, the Forest Park area has seen the bulk of its prosperity shift southward and new development is fewer and further between in this post WWII-era suburb. Nevertheless, GA 331 continues to serve the needs of the residents of the area, military traffic to Fort Gillem, the Farmers Market and as access from I-75 to GA 85 since the original interchange was largely removed in 1976.