The calculated distance (air line) between Iharan̈a and Maroantsetra is approximately 145 miles respectively 234 kilometers.
By car or train, the actual journey to Maroantsetra is certainly longer, as only the direct route (as the crow flies) between Iharan̈a and Maroantsetra has been calculated here.
Air line (approximately)
234 kilometers
126 nautical miles