Distance between cities › USA › South Dakota › Mount Vernon, SD › Distance from Mount Vernon to Roy Book Hotels

Distance from Mount Vernon, SD to Roy, MT

Distance

698 mi

Time

12 hours 39 mins

Gas Cost

$65 - $127

There are 574.56 miles from Mount Vernon to Roy in northwest direction and 698 miles (1,123.32 kilometers) by car, following the I-90 route.

Mount Vernon and Roy are 12 hours 39 mins far apart, if you drive non-stop .

This is the fastest route from Mount Vernon, SD to Roy, MT.

Please note the time difference between Mount Vernon, SD and Roy, MT is 1 hour. The current time in Mount Vernon is 1:59 pm and the current time in Roy is 12:59 pm.

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Lowest Price Rental Cars in Mount Vernon, SD

Planning on renting a car to go from Mount Vernon, SD to Roy, MT? Here there are some offers to rent a car in Mount Vernon, SD

Small

From $14

Intermediate

From $18

Full-size

From $24

SUVs

From $28

Vans

From $40

Compare rental car prices in Mount Vernon »

Gas Consumption and Emissions

A car with a fuel efficiency of MPG will need 28.04 gallons of gas to cover the route between Mount Vernon, SD and Roy, MT.

The estimated cost of gas to go from Mount Vernon to Roy is $91.46.

During the route, an average car will release 549.34 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 Mount Vernon, SD and Roy, MT

If you want to meet halfway between Mount Vernon, SD and Roy, MT or just make a stop in the middle of your trip, the exact coordinates of the halfway point of this route are 44.905933 and -104.224759, or 44º 54' 21.3588" N, 104º 13' 29.1324" W. This location is 349.09 miles away from Mount Vernon, SD and Roy, MT and it would take approximately 6 hours 19 mins to reach the halfway point from both locations.

Closest City or Town to Halfway Point

The closest town to the halfway point is Alzada, MT, situated 353 miles from Mount Vernon, SD and 345 miles from Roy, MT. It would take 5 hours 54 mins to go from Mount Vernon to Alzada and 6 hours 46 mins to go from Roy to Alzada.