The calculated distance (air line) between Gromiljak and Mrkonjić Grad is approximately 57 miles respectively 92 kilometers.
By car or train, the actual journey to Mrkonjić Grad is certainly longer, as only the direct route (as the crow flies) between Gromiljak and Mrkonjić Grad has been calculated here.
Air line (approximately)
92 kilometers
50 nautical miles