The calculated distance (air line) between Krong Kep and Phnom Penh is approximately 85 miles respectively 137 kilometers.
By car or train, the actual journey to Phnom Penh is certainly longer, as only the direct route (as the crow flies) between Krong Kep and Phnom Penh has been calculated here.
Air line (approximately)
137 kilometers
74 nautical miles