^Reaching the state of Illinois having just crossed the Mississippi River, heading eastbound, August 2018.
Interstate 280 is a beltway around the western and southern edge of the Quad Cities, providing an alternate route to Interstate 80. The north-south section flanking Davenport to the west is in Iowa, but this page will talk about the east-west portion in Illinois, flanking the Quad Cities to the south. Davenport and Bettendorf are the western and eastern Quad Cities in Iowa, respectively, while Rock Island and Moline are the western and eastern Quad Cities in Illinois, respectively. The eastern reaches of Interstate 280 carry Interstate 74's routing, until Interstate 280 ends at the point where Interstate 74 turns southerly and Interstate 80 turns from southerly to easterly-- a "ricochet" interchange, as I like to call it (not a technical term). Interstates 80, 74, and 280 can all be used to pass through the Quad Cities area from west to east or vice versa; however, I personally prefer using Interstate 280, because it has the fewest access points (i.e. interchanges) and the lightest traffic.
Exits are numbered in increasing order from west to east, from the bridge across the Mississippi River out of Iowa, east to the end at the "ricochet," as I've called it. Interstate 280 has one cohesive set of mileage and exit numbers that do not start over at the state border (like Interstate 270's numbers do). As Interstate 280 crosses into Illinois after ten miles of traversing through Iowa, mile numbers in Illinois start at about ten.
Once Interstate 280 is done traveling ten miles south through parts of Iowa territory, it crosses the Mississippi River into Illinois and turns easterly...
The first exit Interstate 280 reaches in Illinois is Exit 11A, for Illinois 92 west toward Andalusia, Illinois:
Exit 11B completes the set of offramps at this cloverleaf interchange, and this ramp leads to Illinois 92 east toward Rock Island:
Though Interstate 280 passes over US Route 67 with no direct access, exit 15 to Airport Road and Milan can provide an indirect link to that highway:
Exit 18A is the first half of a compressed cloverleaf interchange leading to a north-south highway carrying US Route 6 and the northernmost portion of Interstate 74; this first ramp leads to US Route 6 east (south) and the entrance to the Quad City Airport:
Exit 18B, the latter ramp of the cloverleaf, leads to Interstate 74 and US Route 6 north into the heart of Moline; it is at this point that Interstate 74 joins Interstate 280 east (the westbound sign says "exit 5A" because it uses Interstate 74's numbering system):
Interstate 280 travels east with Interstate 74 for another nine miles, and then comes to an end at the ricochet interchange. This cloverleaf interchange kicks off with a ramp sending Interstate 74 farther southeastward, toward Galesburg and Peoria:
The second ramp at the cloverleaf leads to Interstate 80 northward and westward, toward Interstate 88 and toward Des Moines. Continuing straight ahead to the east will put you on Interstate 80 east toward Chicago, which is probably what most travelers want!