The calculated distance (air line) between Kinshasa and Mbanza-Ngungu is approximately 72 miles respectively 115 kilometers.
By car or train, the actual journey to Mbanza-Ngungu is certainly longer, as only the direct route (as the crow flies) between Kinshasa and Mbanza-Ngungu has been calculated here.
Air line (approximately)
115 kilometers
62 nautical miles