The calculated distance (air line) between Monbetsu-honchō and Sapporo is approximately 55 miles respectively 88 kilometers.
By car or train, the actual journey to Sapporo is certainly longer, as only the direct route (as the crow flies) between Monbetsu-honchō and Sapporo has been calculated here.
Air line (approximately)
88 kilometers
47 nautical miles