Alabama state line to I-185

I-85 enters the state of Georgia from Alabama via twin bridges over the Chattahoochee River, and then it immediately skirts the town of West Point, with Kia's multibillion-dollar plant located adjacent to the freeway just east of West Point. After leaving West Point, I-85 enters the LaGrange area, the first large town in Georgia on its route to the northeast. Northeast of LaGrange, I-85 has an interchange with the long spur freeway, I-185, to the Columbus metropolitan area. This is the only connection between Columbus and the Interstate Highway System.

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.^[3]

From I-185 through Atlanta

From LaGrange, I-85 heads northeastward toward Atlanta. 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. The highway then intersects I-285 at its southwest end in College Park. This interchange is one of the most complex interchanges in the country, as I-285 and I-85 stay side by side through the interchange, which actually has two parts. The interchange also features many other, less important local access roads at the same time; meanwhile providing access to Hartsfield–Jackson Atlanta International Airport. 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. At the southern edge of Downtown Atlanta, this freeway has an interchange with the major east–west Interstate Highway, I-20. 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.

Atlanta to South Carolina state line

Heading northbound after the Brookwood Interchange with I-75, I-85 is routed along a 10-lane-wide viaduct from the Buford Highway Connector (exit 86) to SR 400 (exit 87). Continuing northeast of Atlanta, I-85 continues through the northeastern suburbs, bypassing Chamblee and Doraville, where there is another intersection with I-285 (nicknamed Spaghetti Junction). The Interstate then travels through the northeastern suburbs of Atlanta, including Lilburn, Duluth, Lawrenceville, and Buford. The Interstate has freeway interchanges with SR 316 in Duluth and I-985 in Suwanee, which provides a link to Gainesville. Satellite Boulevard within Gwinnett County parallels I-85 to the west as an arterial frontage road.

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. At Lake Hartwell, which was formed by the damming of the Savannah River, I-85 crosses the Savannah River into South Carolina.

Express lanes

I-85 has the first express lanes in Georgia, located in Gwinnett and DeKalb counties; they were originally high-occupancy vehicle lanes (HOV lanes). From Chamblee–Tucker Road (exit 94) to Old Peachtree Road (exit 109), travelers that utilize the converted 15.5-mile (24.9 km) lanes will be charged a toll varying from 10 to 90 cents per mile (6.2–55.9 ¢/km), depending on traffic conditions and usage. Though not signed on the freeway, they are high-occupancy toll lanes (HOT lanes), which means registered transport vehicles, carpools with three or more occupants, motorcycles, and busses are exempt from toll charges as long as they are registered as such.^[4] Tolls are collected using an electronic toll collection system. All travelers that use the lane must have a Peach Pass sticker to avoid fines.^[5][6] Starting in November 2014, SunPass (Florida) and NC Quick Pass (North Carolina) are interoperable with Peach Pass, allowing motorists with those transponders to use the express lanes.

On November 3, 2018, an extension to the express lanes opened, from its former ending at Old Peachtree Road to Hamilton Mill Road (exit 120).^[7] After this extension, four more northbound exit points were added: at SR 317 (exit 111), I-985 (exit 113), SR 20 (exit 115), and at its end at Hamilton Mill Road (exit 120). In addition, four new access points were added to the southbound express lanes: at SR 20, SR 317, Old Peachtree Road, and at the connection to the preexisting express lanes.^[8] The project costed $178 million (equivalent to $213 million in 2023^[9]).^[10] The express lanes extension will incur a separate charge from the existing express lanes. This is to decrease the impact of high congestion on the existing express lanes on the dynamic pricing of the express lanes extension, since lower congestion is expected on the new extension of the express lanes.^[11]

Funds generated from the express lanes will be used to defray the costs of construction, operations, and maintenance of the lanes. Long-term revenue allocation is being studied and a decision about future excess revenues will be made later in the project process.^[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.^[5] Detractors point out that existing infrastructure was reused for the express lanes and that commute times on the nonpaying travel lanes have doubled since implementation.^[13][14]