The calculated distance (air line) between Mrkonjić Grad and Banja Luka is approximately 26 miles respectively 41 kilometers.
By car or train, the actual journey to Banja Luka is certainly longer, as only the direct route (as the crow flies) between Mrkonjić Grad and Banja Luka has been calculated here.
Air line (approximately)
41 kilometers
22 nautical miles