The calculated distance (air line) between Greystones and An Muileann gCearr is approximately 59 miles respectively 95 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 Greystones and An Muileann gCearr has been calculated here.
Air line (approximately)
95 kilometers
51 nautical miles