Which state am I in? How interstate mile markers change at the Kansas City state line

Five interstates, two ways of counting

Around Kansas City, five interstates cross the Kansas–Missouri line: I-70, I-35, I-670, I-435 and I-635. They do not all handle the crossing the same way, and that is the root of most confusion when a driver gives a mile marker from somewhere near the line.

The long-distance routes, I-70 and I-35, are numbered state by state. Each state counts miles from where the interstate enters it, so the numbers jump at the line. The loop and spur routes built around the metro, I-435 and I-635, count once from end to end and carry the same sequence through both states. I-670, the short downtown connector, borrows its Missouri exit numbers from the downtown loop.

I-70: from the 420s straight to zero

Kansas counts I-70's miles from the Colorado line, so by Kansas City, Kansas the numbers are in the 400s. Missouri counts from its own western border. Heading east, the numbers run like this:

• Exit 410, 110th Street, and exit 411, I-435. By the Kansas Speedway.
• Exit 418, I-635.
• Exit 420, US-69 and 18th Street. Where the Kansas Turnpike designation ends.
• Exits 421 to 423. Downtown Kansas City, Kansas, including the connection to I-670 and I-35 at 421B.
• The state line, at about mile 422.8. On the Lewis and Clark Viaduct.
• Missouri mile 0. The count restarts, and the first exits are the downtown loop's, numbered 2 with a letter, from 2A onward.
• Exit 8, I-435. The second time I-70 meets I-435, this time on the Missouri side.

I-35: from the 230s to zero

I-35 works the same way. Kansas counts from the Oklahoma line, so through Olathe, Lenexa, Merriam and Kansas City, Kansas the exits are in the 200s. The last Kansas exits before the line are 234, for US-169 at the 7th Street Trafficway and Rainbow Boulevard, and 235, at Cambridge Circle. The state line sits at about mile 235.3.

Across the line, Missouri starts I-35 at zero. The first Missouri exits carry the number 1 with a letter, and then I-35 joins the downtown loop, where its exits are numbered 2 with a letter, just like I-70's. North of the river, Missouri's I-35 exit numbers climb with the mileage again: the I-29 split is exit 8B, Liberty is exits 16 to 20, and Cameron is exits 52 and 54.

The practical effect is that on both I-70 and I-35, a big number means Kansas and a small one means Missouri. The trouble only starts when the person taking your call does not know which highway you mean, or assumes the wrong state.

I-435: one count around the whole loop

I-435 is different. Its mile zero is at I-35 in Lenexa, Kansas, and the mileage does not start over when it crosses into Missouri. It counts continuously around the loop, with one exception: where I-435 shares pavement with I-29 near the airport, I-29's mile and exit numbers take precedence. The key points are:

• Miles 0 to about 21: Kansas. From Lenexa, I-435 runs north through Kansas City, Kansas. Exit 18, for K-5 north, is the last Kansas exit.
• About mile 21: the Missouri River. The river is the state line here, and the bridge carries I-435 from Wyandotte County, Kansas into Platte County, Missouri. Exit 22, Route 45 at Parkville, is the first Missouri exit.
• Mile 22 to about 75: Missouri. Around the north, east and south sides of the loop, including the interchange with I-70 at I-70's exit 8.
• About mile 75.5: State Line Road. Exit 75A, Wornall Road, is the last Missouri exit. I-435 crosses back into Kansas near State Line Road and 103rd Street.
• Beyond mile 75.5: Kansas again. Exits 77A and 77B, Roe Avenue and Nall Avenue, are in Overland Park, and the loop continues back toward Lenexa.

I-635 and I-670

I-635 follows I-435's approach. Its mile zero is at I-35 in Overland Park, Kansas, and its mileage does not reset in Missouri. It runs north through Kansas City, Kansas, meeting I-70 at I-70's exit 418, and crosses the Missouri River into Riverside, Missouri at about mile 9. It ends at I-29 in Kansas City, Missouri at about mile 12.7. So on I-635, anything below about 9 is Kansas and anything above is Missouri.

I-670 is a short connector of under three miles. It leaves I-70 in Kansas City, Kansas, crosses the Kansas River and the state line, and forms the south side of the downtown freeway loop in Kansas City, Missouri. On the Missouri side its exits use the loop's 2-plus-letter numbers. If you are anywhere on I-670, say so by name, because the exit numbers alone overlap with I-70 and I-35 on the loop.

How to tell which state you are in

When you are tired, stressed or unfamiliar with the city, it is easy to lose track of which side of the line you are on. Several clues can settle it quickly:

• The size of the number on I-70 or I-35. Exits and mile markers in the 400s on I-70, or the 200s on I-35, mean Kansas. Low numbers mean Missouri.
• The range on I-435 and I-635. On I-435, roughly miles 21 to 75 are Missouri and the rest is Kansas. On I-635, Missouri starts at about mile 9.
• The last river you crossed. On I-435 and I-635 the Missouri River is the state line. On I-70 the line is on the Lewis and Clark Viaduct.
• City names on the exit signs. Overland Park, Lenexa and Olathe are in Kansas. Independence, Liberty, Parkville and Riverside are in Missouri. "Kansas City" is on both sides and settles nothing.
• Your phone's map. A map app will show your position against the state line, and a dropped pin you can share removes any doubt.

Why the state matters on an emergency call

The two states have different highway patrols with different cellular numbers. In Missouri it is the State Highway Patrol at *55, and in Kansas it is the Kansas Highway Patrol at *47, or *582 on the Kansas Turnpike. Calling the right one gets a trooper from the right agency started.

911 works everywhere, but near a state line do not assume the call reached the center for your side. The FCC has said wireless 911 calls have traditionally been routed by the location of the cell tower that handles them, which can send a call to a neighboring jurisdiction, and in 2024 it adopted rules requiring carriers to route calls by the caller's location instead. The simplest protection is to say the state in your first sentence.

The state matters to a tow company too. On both sides of the line the approach to you can mean choosing a river crossing or an interchange to get turned around, so the state and direction decide the route as much as the mile marker does. Our heavy-duty towing covers both sides, and the service area page shows how far we run.

Exactly what to say

Put the details in the same order every time: highway, direction, state, mile marker or last exit, then where the truck is sitting. For example: "I-70 westbound, in Missouri, just before the Lewis and Clark Viaduct, right shoulder." Or: "I-435 northbound, in Kansas, about mile 20, before the Missouri River bridge." Or: "I-35 southbound, in Kansas, past exit 235, left lane blocked."

After that, the tow company needs the truck details: tractor and trailer type, loaded or empty, whether it still builds air and rolls, and where it should go. Our post on what to tell dispatch for a heavy tow covers that part of the call in full, and our guide to breaking down on I-70 in Kansas City walks through the I-70 exits on both sides. For local detail, see our pages for Kansas City, Kansas and Kansas City, Missouri.

Related reading

Broke Down on I-35 North: Liberty and Kearney to Cameron — Turn on your hazard flashers, get as far out of the lanes as you safely can, and call 911 or the Missouri State Highway Patrol at *55.

Broke Down on I-70 in Kansas City: Kansas and Missouri — Get as far out of the lanes as you safely can, turn on the hazard flashers and call 911, *55 on the Missouri side or *47 on the Kansas side.

Where Semis Can and Can't Drive in Kansas City — Semis may use Kansas City's interstates and state highways at legal size and weight: 102 inches wide and 80,000 pounds gross on the interstate.