The calculated distance (air line) between Boma and Mbanza-Ngungu is approximately 131 miles respectively 210 kilometers.
By car or train, the actual journey to Mbanza-Ngungu is certainly longer, as only the direct route (as the crow flies) between Boma and Mbanza-Ngungu has been calculated here.
Air line (approximately)
210 kilometers
113 nautical miles