MileCheckOregon is where MileCheck started — the app was first built for a driver working these exact roads through a winter (that story is here). From the I-5 corridor to the Columbia River Gorge and the Blue Mountains, Oregon's highways run on mile markers. Here's how they work, where they matter most, and how to see your exact one plus live TripCheck conditions in real time.
How Oregon numbers its highways
Oregon's mileposts count up from a route's southern or western starting point — I-5 counts up from the California line, and I-84 counts up from Portland heading east. One quirk worth knowing: inside ODOT's own data, highways carry historic names instead of route numbers — I-84 is internally the "Old Oregon Trail," and I-5 is the "Pacific Highway." You'll never see that on a sign, but it's why raw state data is hard to read, and it's part of what MileCheck translates for you. And Oregon is getting more precise: ODOT has been adding half-mile markers along its highways — posts at 224.5 as well as 224 — so crews, dispatchers, and drivers can pinpoint an incident twice as tightly. Mile marker data for every Oregon highway is bundled into the app and works offline — and the app already reads in tenths, so it's ahead of the signs.
The corridors people actually drive
- I-5 runs about 308 miles from the California border at the Siskiyous through Medford, Eugene, Salem, and Portland.
- I-84 leaves Portland east through the Columbia River Gorge, climbs the Blue Mountains past Pendleton and La Grande, and reaches the Idaho line near Ontario at about mile 375.
- I-205 and I-405 loop Portland.
- US-101 follows the entire coast; US-97 runs the length of Central Oregon through Bend; US-26 crosses Mount Hood at Government Camp; US-20 — the longest road in America — crosses the state through Santiam Pass.
Where mile markers matter most: the grades
Three stretches define Oregon driving. The Siskiyou Summit on I-5, just north of the California line around milepost 6, is the highest point on the entire interstate — chains are routine there in winter. The Columbia River Gorge on I-84 funnels freezing rain that can glaze the road for miles. And Cabbage Hill — the double-hairpin, six-percent grade on I-84 between Pendleton and La Grande, around mileposts 216 to 224 — is one of the most demanding pieces of interstate in the West. When ODOT closes any of them, the closure is announced by milepost.
Seasonal and weather closures
Oregon's closures are weather stories. East winds push freezing rain through the Columbia River Gorge and I-84 can close outright — sometimes for a day or more — between Troutdale and Hood River. In the Blues, ODOT regularly shuts I-84 between Pendleton and La Grande when winter crashes pile up on Cabbage Hill. Chains are required over the Siskiyous, Government Camp, and Santiam Pass many times each winter. Every one of these is announced by milepost, so getting the live TripCheck alert before you commit to a grade can save you hours of sitting in a closure — or a long backtrack.
Live TripCheck alerts, in one place
MileCheck pulls live road alerts straight from ODOT's TripCheck system: closures, crashes, construction, chain requirements, and winter road conditions, tied to the mile marker and direction so you can see what's ahead of you on your route — not just a dot on a statewide map.
Everyday and emergency
Whether you're timing the Gorge in an ice storm, hauling over Cabbage Hill in January, or reporting a breakdown on US-97 where the signal drops, the mile marker is the location Oregon's roads run on. MileCheck shows yours in real time, down to a tenth of a mile, even with no cell service.
Keep reading
Nearby state guides: California · Idaho · Nevada · Washington
Oregon drawbridges: every movable bridge, its opening rules and live status →
Essentials: What to tell 911 on the highway · How to find your mile marker · Browse the live mile marker map · All 50 states