Atlanta Airport (ATL): A Traveler's Guide
Hartsfield-Jackson Atlanta International Airport (ATL) is the world's busiest airport by passenger traffic and Delta Air Lines' primary hub, so odds are good you'll pass through it on a US connection even if you have no reason to visit Atlanta itself.
Terminal layout
ATL is built as one long spine: a Domestic Terminal (with concourses T, A, B, C, D and E) and, at the far end, Concourse F, home to the Maynard H. Jackson Jr. International Terminal where most non-US arrivals and departures happen. The underground Plane Train links every concourse and is genuinely the fastest way to move between them - walking the full length of the airport can take 30-40 minutes, while the train covers it in a fraction of that, supplemented by long moving walkways if you'd rather stay above ground for a shorter hop.
Immigration, customs and security
If you're arriving internationally, you'll clear US Customs and Border Protection at Concourse F, collect any checked bags, and if you're connecting onward, recheck them and pass back through security - a process that eats time. Give yourself 2-3 hours for an international-to-domestic connection. Domestic-to-domestic connections are far simpler since you generally stay airside; 60-90 minutes is comfortable, though it can be tighter on a single ticket with the same airline. Security lines are usually manageable outside of the 5-7pm peak, when the concourses get genuinely crowded.
Getting into the city
MARTA's train (Red or Gold line) runs directly from the airport's own station to Five Points in downtown Atlanta in about 15-20 minutes for roughly $2.50 - by far the cheapest and often the fastest option, especially in rush-hour traffic. Taxis and rideshares take 20-40 minutes to downtown depending on traffic and typically run $25-40; Buckhead or the northern suburbs will cost more and take longer.
Practical tips
If your connection routes through Concourse F, build in extra buffer even for domestic-to-domestic legs, since immigration and customs delays there can cascade. And if you're just passing through, the Plane Train's announcements name each concourse clearly, so you can safely zone out and just listen for your stop rather than watching the doors.