Distance between cities › USA › Montana › Boulder, MT › Distance from Boulder to Armstrong Book Hotels

Distance from Boulder, MT to Armstrong, MO

Distance

1,343 mi

Time

1 day

Gas Cost

$125 - $243

There are 1,092.63 miles from Boulder to Armstrong in southeast direction and 1,343 miles (2,161.35 kilometers) by car, following the I-29 route.

Boulder and Armstrong are 1 day far apart, if you drive non-stop .

This is the fastest route from Boulder, MT to Armstrong, MO. The halfway point is Kadoka, SD.

Please note the time difference between Boulder, MT and Armstrong, MO is 1 hour. The current time in Boulder is 12:01 am and the current time in Armstrong is 1:01 am.

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Lowest Price Rental Cars in Boulder, MT

Planning on renting a car to go from Boulder, MT to Armstrong, MO? Here there are some offers to rent a car in Boulder, MT

Small

From $14

Intermediate

From $18

Full-size

From $24

SUVs

From $28

Vans

From $40

Compare rental car prices in Boulder »

Gas Consumption and Emissions

A car with a fuel efficiency of MPG will need 53.95 gallons of gas to cover the route between Boulder, MT and Armstrong, MO.

The estimated cost of gas to go from Boulder to Armstrong is $175.99.

During the route, an average car will release 1,057.01 pounds of CO₂ to the atmosphere. The carbon footprint would be 0.79 pounds of CO₂ per mile.

Average USA gas price used for calculation is $3.26 per gallon of regular gas. Price last updated on March 12, 2026.
Read more about our CO₂ calculation.

Halfway Point Between Boulder, MT and Armstrong, MO

If you want to meet halfway between Boulder, MT and Armstrong, MO or just make a stop in the middle of your trip, the exact coordinates of the halfway point of this route are 43.852177 and -101.521194, or 43º 51' 7.8372" N, 101º 31' 16.2984" W. This location is 671.69 miles away from Boulder, MT and Armstrong, MO and it would take approximately 12 hours to reach the halfway point from both locations.

Closest City or Town to Halfway Point

The closest town to the halfway point is Kadoka, SD, situated 690 miles from Boulder, MT and 734 miles from Armstrong, MO. It would take 10 hours 36 mins to go from Boulder to Kadoka and 10 hours 32 mins to go from Armstrong to Kadoka.