The calculated distance (air line) between Sandyford and An Muileann gCearr is approximately 49 miles respectively 79 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 Sandyford and An Muileann gCearr has been calculated here.
Air line (approximately)
79 kilometers
43 nautical miles