The calculated distance (air line) between Ariel and Rosh Ha‘Ayin is approximately 13 miles respectively 22 kilometers.
By car or train, the actual journey to Rosh Ha‘Ayin is certainly longer, as only the direct route (as the crow flies) between Ariel and Rosh Ha‘Ayin has been calculated here.
Air line (approximately)
22 kilometers
12 nautical miles