The calculated distance (air line) between Newcastle West and An Muileann gCearr is approximately 103 miles respectively 166 kilometers.
By car or train, the actual journey to An Muileann gCearr is certainly longer, as only the direct route (as the crow flies) between Newcastle West and An Muileann gCearr has been calculated here.
Air line (approximately)
166 kilometers
90 nautical miles