In Downtown Atlanta, the Downtown Connector or 75/85 (pronounced "seventy-five eighty-five") is the concurrent section of Interstate 75 and Interstate 85 through the core of the city. Beginning at the I-85/Langford Parkway interchange, the Downtown Connector runs generally due north, meeting the west–east I-20 in the middle. Just north of this is the Grady Curve around Grady Memorial Hospital. Continuing north, the terminus of the Downtown Connector is the Brookwood Interchange or Brookwood Split in the Brookwood area of the city. The overall length of the Downtown Connector is approximately 7.5 miles (12 km). Since the 2000s, it has been officially named James Wendell George Parkway for most of its length, although it is still designated the Connector in the mainstream. It also has unsigned designations State Route 401 (I-75) and State Route 403 (I-85) along its length, due to I-75 and I-85 having 400-series reference numbers.

The Downtown Connector carries more than 437,000 vehicles per day at its busiest point — just south of 10th Street in Midtown, while the least traveled portion carries 243,000 vehicles per day — just south of Fulton Street, near the interchange with Interstate 20. The area around the connector and associated interchanges are considered one of the ten-most congested stretches of interstate in the U.S. Due to this fact, many motorists often compare Atlanta to Los Angeles, which is also known for its notoriously-congested freeway system.

The highway is fully instrumented with Intelligent transportation system (ITS) devices. There are more than 25 closed-circuit television cameras between the Langford Parkway interchange (south end) and the Brookwood Interchange (north end). Additionally, the Downtown Connector has three large overhead electronic message signs, and four smaller HOV-dedicated message signs on the median barrier wall. Traffic flow data is gathered through a video detection system, using pole-mounted black-and-white cameras spaced every 1⁄3 mile (0.54 km) on both sides of the roadway. All video and data is fed into the GDOT's Transportation Management Center (TMC), via fiber-optic cable located under the shoulders of the roadway. Virtually all entrance ramps are metered, with the exception of the freeway-to-freeway connection ramps from I-20. As with every other freeway inside the Perimeter, the Downtown Connector is lined with streetlights mounted in the center median, with high-mast lighting at major interchanges.

Atlanta's skyline, both Downtown and Midtown, can be seen from the highway, especially at the northern and southern ends.

On December 14, 1944, the Georgia State Highway Department, the predecessor agency to the Georgia Department of Transportation (GDOT), collaborated with the city of Atlanta, Fulton County, and the Bureau of Public Roads (BPR), the predecessor to the Federal Highway Administration (FHWA) to work on a plan to improve traffic and connectivity within the Atlanta area. Chicago-based H.W. Lochner & Company, a transportation engineering firm which had been formed earlier that year, was hired to provide a comprehensive transportation plan for the region, using data conducted by the BPR and the state highway department from 1936 to 1945, and future growth projections. The report, which was released on January 10, 1946, recommended a total of six radiating expressways be constructed in the city, with the intent of being integrated into what later became the Interstate Highway System, which at the time was expected to eventually be authorized by Congress. The report recommended that four of these expressways converge into a single north-south route through downtown, which was referred to at the time as both the "Downtown Connector" and the "Downtown Connector Expressway".

Work of the first section of the Downtown Connector, located between Williams Street and the Brookwood Interchange, as well as the approximately 1⁄3 mi (0.54 km) stretch of what is now I-85 north to Peachtree Street, began in September 1948, and was dedicated and opened to traffic on September 25, 1951. The 0.6 mi (0.97 km) stretch from Piedmont Avenue to Williams Street opened on May 5, 1959. Work on a southern stretch of the Connector, a 1.4-mile (2.3 km) section between University Avenue and Richardson Street, began in March 1955, and was dedicated and opened on July 25, 1957. Construction on the final stretch, the 2.3-mile (3.7 km) stretch between Richardson Street and Piedmont Avenue, including the interchange with I-20, began on February 26, 1962, and was opened to traffic on September 18, 1964. A ribbon-cutting ceremony for the Downtown Connector, attended by Governor Carl Sanders, FHWA administrator Rex Marion Whitton, and Atlanta mayor Ivan Allen Jr. was held inside the Georgia State Capitol on October 15, 1964.

Initial construction of the highway displaced parts of Techwood Drive and Williams Street in Midtown Atlanta. It also destroyed street grids east and south of downtown, dividing Sweet Auburn in two and the interchange with I-20 leveling the northern part of the Washington-Rawson district. The proposed I-485 was originally planned by the Georgia Department of Transportation to carry some south–north traffic through the eastern side of the city, but most of this was canceled in the 1970s by the then-governor of Georgia, Jimmy Carter. Parts of that road are now I-675 and SR 400.

The highway was heavily reconstructed during the 1980s as part of GDOT's Freeing the Freeways program to widen Atlanta-area freeways, with most of the Connector's width being doubled from three to six or seven lanes in each direction. The project included work to increase lanes from six to eight on I-20, I-75, I-85, and I-285 ("The Perimeter"), as well as ten lanes on the downtown connector, involving 126 total miles and was phased over 13 years between 1976 and 1988. The improvement campaign also included elimination of sharp curves and grades, left-hand exits, excessive interchanges, and short acceleration/deceleration lanes.