The calculated distance (air line) between Portarlington and An Muileann gCearr is approximately 26 miles respectively 41 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 Portarlington and An Muileann gCearr has been calculated here.
Air line (approximately)
41 kilometers
22 nautical miles