The calculated distance (air line) between Buncrana and An Muileann gCearr is approximately 111 miles respectively 179 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 Buncrana and An Muileann gCearr has been calculated here.
Air line (approximately)
179 kilometers
97 nautical miles