The calculated distance (air line) between Roches Noire and Petite Rivière is approximately 18 miles respectively 29 kilometers.
By car or train, the actual journey to Petite Rivière is certainly longer, as only the direct route (as the crow flies) between Roches Noire and Petite Rivière has been calculated here.
Air line (approximately)
29 kilometers
16 nautical miles