The calculated distance (air line) between Samut Songkhram and Nakhon Sawan is approximately 159 miles respectively 255 kilometers.
By car or train, the actual journey to Nakhon Sawan is certainly longer, as only the direct route (as the crow flies) between Samut Songkhram and Nakhon Sawan has been calculated here.
Air line (approximately)
255 kilometers
138 nautical miles