The calculated distance (air line) between Arrasate / Mondragón and Oñati is approximately 5 miles respectively 7 kilometers.
By car or train, the actual journey to Oñati is certainly longer, as only the direct route (as the crow flies) between Arrasate / Mondragón and Oñati has been calculated here.
Air line (approximately)
7 kilometers
4 nautical miles