MileCheckMississippi's highways run in three directions: I-55 north-south through the middle, I-20 east-west through Jackson, and I-10 along the Gulf. Here's how mile markers work across the state — plus the one road that's been using mileposts since before the interstates existed.
How Mississippi numbers its highways
Mississippi's mileposts count up from where a route enters the state on the south or west and climb as you head north or east. On I-55, mile 0 sits at the Louisiana line and the numbers run to roughly 290 at the Tennessee line near Memphis. State routes carry the MS prefix. Mile marker data for every Mississippi highway is bundled into MileCheck and works offline — handy in the rural stretches where the signal fades.
The corridors people actually drive
- I-55 runs the state north-south, about 290 miles from the Louisiana line through Jackson and Grenada to the Tennessee line.
- I-20 crosses east-west at Jackson, linking Vicksburg to Meridian and on toward Alabama.
- I-10 hugs the Gulf through Gulfport and Biloxi.
- I-59 and US-49 connect the coast up toward Hattiesburg and Jackson.
An aside: the Natchez Trace runs on mileposts too
The Natchez Trace Parkway — the 444-mile parkway that starts at Natchez and runs northeast across the state toward Nashville — uses its own historic milepost system, with milepost 0 at Natchez. Every site, trailhead, and pull-off along the Trace is identified by milepost, not exit number. It's a nice reminder that mileposts aren't just an interstate convention; they're the oldest addressing system American roads have.
Hurricane season on the Gulf
When a hurricane threatens the Mississippi coast, evacuations move north off I-10 — up US-49 toward Hattiesburg and Jackson, and up I-55 and I-59 away from the water. Those movements are coordinated by route and mile marker: where traffic is stacking, which exits have fuel, where lanes are adjusted. Live alerts before you leave, and an exact milepost while you're in the crawl, keep you oriented on the hardest driving day of the year.
Live MDOT alerts, in one place
MileCheck pulls live road alerts straight from MDOT: closures, crashes, and construction, tied to the mile marker and direction so you can see what's ahead of you on your route — a wreck north of Jackson, a work zone on I-20, or a coastal closure during a storm.
Everyday and emergency
Whether you're running I-55 to Memphis, cruising the Trace at 50 mph, or reporting a breakdown on a rural highway, the mile marker is the location Mississippi's roads run on. MileCheck shows yours in real time, down to a tenth of a mile, even where the cell signal drops — and it works on CarPlay and Android Auto too.
Keep reading
Nearby state guides: Alabama · Arkansas · Louisiana · Tennessee
Mississippi drawbridges: every movable bridge, its opening rules →
Essentials: What to tell 911 on the highway · How to find your mile marker · Browse the live mile marker map · All 50 states