After leaving West Point, I-85 enters the LaGrange area, the first large town in Georgia on its route to the northeast.

An 18-mile (29 km) stretch between the Alabama line and exit 18 in LaGrange is serving as an environmental and technological testbed for a project called The Ray, a partnership involving federal and state officials, the private sector, academia and philanthropic organizations.

Among the projects are a solar-paved roadway, enhanced road striping for autonomous vehicles, and plantings along the right-of-way to improve runoff and possibly serve as a harvestable crop.

Before reaching Atlanta, the highway crosses the CSX Transportation A&WP Subdivision twice (in the Grantville area) and passes through the suburbs of Moreland, Newnan, Fairburn, and Union City.

I-85 then runs along the northwestern boundary of the airport in East Point, providing access to the domestic terminal.

At the southwestern edge of Atlanta's city limits, I-85 merges with I-75 to form the Downtown Connector, which is 12 to 14 lanes wide.

The two freeways then skirt the eastern edge of downtown, running due north, passing through the Georgia Tech campus and the Atlantic Station section of Atlanta before the two highways split, with I-75 exits via the right three lanes and then heads northwest while I-85 uses the left three lanes and then heads northeast.

The Interstate then travels through the northeastern suburbs of Atlanta, including Lilburn, Duluth, Lawrenceville, and Buford.

I-85 eventually leaves the Atlanta metropolitan area and narrows down to four lanes (two in each direction) past exit 129 as the highway continues into the rural parts of northeast Georgia.

[12] Proponents for the express lanes say it is to provide commuters with a more reliable, free-flow commute option; complement the state's multimodal approach to managing traffic demand; and establish the vision for a future system of HOT lanes in the region.

[13][14] Originally constructed as a four- to six-lane expressway in the 1950s, the stretch of I-85 between the southern merge with I-75 and North Druid Hills Road was reconstructed as part of the Georgia Department of Transportation (GDOT)'s Freeing the Freeways program.

This project included rebuilding all overpasses, new HOV-ready ramps (with the system implemented in 1996), and a widening of freeway capacity.

Concurrent with this project was the construction of the Civic Center station as part of the West Peachtree Street overpass, which opened in December 1981.

The 30-mile (48 km) section between LaGrange and Newnan was incomplete for a much-longer time that the rest of I-85 in Georgia and required a two-lane detour on US 27 and US 29 between those cities.

However, then-Governor Ernest Vandiver worked to make sure the highway traversed his home county of Franklin, a stretch that now bears his name.

I-485 was a short freeway in Atlanta (now Freedom Parkway) that was incomplete for many years and then decommissioned due to local opposition.