The calculated distance (air line) between Kostanjevica na Krki and Grosuplje is approximately 37 miles respectively 60 kilometers.
By car or train, the actual journey to Grosuplje is certainly longer, as only the direct route (as the crow flies) between Kostanjevica na Krki and Grosuplje has been calculated here.
Air line (approximately)
60 kilometers
33 nautical miles