Orbit I-15 speed limit in Montana
80 mphUsual limit · 65 to 80 mph along the way
Mostly 80 mph: about 83% of I-15 in Montana is posted at 80. Limits run from 65 to 80 mph along the way.
How much of I-15 is at each limit
Questions
What is the speed limit on I-15 in Montana?
Mostly 80 mph: about 83% of I-15 in Montana is posted at 80. Limits run from 65 to 80 mph along the way.
What is the highest speed limit on I-15 in Montana?
80 mph, on 83% of its length in Montana.
Can the limit be lower than this?
Yes. Work zones, bad weather and local signs can set a lower limit. The posted sign is always the limit.
How does Orbit know the limit?
Orbit uses state and federal road data and OpenStreetMap, and drivers confirm limits from the road. In the app, the limit for the road you are on shows on the map and in CarPlay.
Posted limits as of October 2026, from state and federal road data and © OpenStreetMap contributors, measured by length of road. Work zones, weather and signs can set a lower limit; always follow the posted sign.
Other Interstates in Montana
I-15 in other states
Orbit shows the limit for the road you're on · coming soon to iPhone and CarPlaySee Orbit SI