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Distance from Harper to Duncan
Route Information
The driving distance from Harper, Kansas to Duncan, Oklahoma is 249.9 mi (402.1 km)
The straight-line (air) distance is 192.0 mi (309.0 km)
The estimated flight time is 0 hr 23 min
The estimated travel time by road is 3 hours 54 minutes
Traveling mixed highways and local roads, long-distance in a south direction. Average speeds around 54 mph.
Location Details
Origin:
Destination:
Journey Summary
Traveling from Harper, Kansas to Duncan, Oklahoma covers 249.9 mi (402.1 km) in a south direction. This mixed highways and local roads, long-distance route typically takes 3 hours 54 minutes under normal conditions.
Drivers have 3 route options between these locations (209.5-249.9 miles / 337-402 km). The primary route shown here saves 6 minutes compared to alternatives.
The route features scenic views, toll sections. with average speeds around 54 mph (87 km/h).
Available Routes
How is the distance calculated?
Driving distances are based on actual road data. We use advanced routing algorithms that consider traffic, tolls, highways, and local streets. For air distances (as the crow flies), we use the Vincenty formula. It's a precise method that accounts for the Earth's shape and provides accuracy up to 0.5 mm.
When multiple route options exist, we display both the shortest and fastest paths. Travel times are estimated based on typical speeds for each road type, though actual times may vary with traffic and weather conditions. All distances are shown in both miles and kilometers for convenience.