Terminal 1 hosts 6 airlines.
Two concourses, no connector
After TSA at GRR’s passenger terminal, the space splits into Concourse A to the left and Concourse B to the right, and there is no sterile connector between them. Allegiant, Frontier, Southwest, and some Delta flights tend to use one side, while American and United frequently show up on the other, but always follow whatever is printed on your boarding pass. If you head into the wrong concourse, you must exit, go back to the main hall, and clear security again.
Single checkpoint feeding both A and B
Security sits on the upper level of the passenger terminal, directly ahead of the ticket counters for Allegiant Air, American Airlines, Delta Air Lines, Frontier Airlines, Southwest Airlines, and United Airlines. All passengers funnel through this single checkpoint before choosing A or B. Local flyers mention that they double‑check the concourse on their boarding pass before joining a TSA line so they only do the screening process once.
Delta’s early cutoff trips people up
Delta publishes a recommendation at GRR to arrive 90 minutes before departure and to finish check‑in with checked bags at least 60 minutes before your flight. FlyerTalk posters flagged this as stricter than other similarly sized airports and say people used to showing up 45 minutes before departure can get burned here. If you are connecting onward on Delta in Detroit or Minneapolis, build that front‑end buffer in Grand Rapids so your bag makes the ride.
Main hall as the crossroads
The main post‑security hall hangs above the gate areas and lines up with both concourse entrances, so you pass through this central zone on the way to every gate. Regulars describe it as their pause point: confirm gate on the screens, check the concourse letter, then commit to A or B. Once you walk down either dead‑end corridor, you are at the mercy of that side’s small gate cluster, and turning back can cost 20–30 minutes including another TSA run.
Parking: garage over surface lots
On the landside approach, GRR’s long‑term garage sits close enough that frequent flyers call the walk to the terminal “very easy” and skip any shuttle. Flyers on parking threads say they willingly pay more for this long‑term garage versus the cheaper surface lots to avoid waiting outside in winter weather. From the garage, plan roughly a 5–7 minute walk to the airline counters and security upstairs.
Small terminal, mostly domestic routes
The passenger terminal handles a tight set of routes for six carriers, with most flights staying within the United States and a few seasonal leisure runs. A Skytrax reviewer calls out that GRR “needs more international,” a common comment from locals who connect in Chicago, Detroit, or Minneapolis for overseas trips. The upside: the building stays manageable, with short walks from check‑in to the gate compared with big hubs.
How regulars work the building
GRR‑based flyers on FlyerTalk say they treat each concourse as a one‑way street: once they pass into A or B, they stay there and don’t roam back toward the split. Road warriors describing their routine use the main hall above the gates as their default workspace before walking down to board. Many pair that with the long‑term garage routine so the whole car‑to‑gate path is a straightforward walk they can repeat trip after trip.
One last tip
Before you even leave the check‑in counter for Allegiant, American, Delta, Frontier, Southwest, or United, look at the concourse letter printed next to your gate number and lock it in. Pick the TSA queue that feeds your side, clear once, and treat the concourse split like a toll booth you only want to pass through a single time.