The calculated distance (air line) between Chefchaouen and Ksar El Kebir is approximately 38 miles respectively 61 kilometers.
By car or train, the actual journey to Ksar El Kebir is certainly longer, as only the direct route (as the crow flies) between Chefchaouen and Ksar El Kebir has been calculated here.
Air line (approximately)
61 kilometers
33 nautical miles