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

Distance from Mount Vernon, SD to Keystone, SD

Distance

284 mi

Time

4 hours 41 mins

Gas Cost

$25 - $49

There are 257.47 miles from Mount Vernon to Keystone in west direction and 284 miles (457.05 kilometers) by car, following the I-90 route.

Mount Vernon and Keystone are 4 hours 41 mins far apart, if you drive non-stop .

This is the fastest route from Mount Vernon, SD to Keystone, SD. The halfway point is Okaton, SD.

Please note the time difference between Mount Vernon, SD and Keystone, SD is 1 hour. The current time in Mount Vernon is 6:36 am and the current time in Keystone is 5:36 am.

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Lowest Price Rental Cars in Mount Vernon, SD

Planning on renting a car to go from Mount Vernon, SD to Keystone, SD? 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 11.39 gallons of gas to cover the route between Mount Vernon, SD and Keystone, SD.

The estimated cost of gas to go from Mount Vernon to Keystone is $35.71.

During the route, an average car will release 223.16 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 $3.14 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 Keystone, SD

If you want to meet halfway between Mount Vernon, SD and Keystone, SD or just make a stop in the middle of your trip, the exact coordinates of the halfway point of this route are 43.894020 and -100.929184, or 43º 53' 38.472" N, 100º 55' 45.0624" W. This location is 141.81 miles away from Mount Vernon, SD and Keystone, SD and it would take approximately 2 hours 20 mins to reach the halfway point from both locations.

Closest City or Town to Halfway Point

The closest town to the halfway point is Okaton, SD, situated 137 miles from Mount Vernon, SD and 147 miles from Keystone, SD. It would take 1 hour 48 mins to go from Mount Vernon to Okaton and 2 hours 3 mins to go from Keystone to Okaton.