The calculated distance (air line) between Halmeu and Piatra Neamţ is approximately 171 miles respectively 275 kilometers.
By car or train, the actual journey to Piatra Neamţ is certainly longer, as only the direct route (as the crow flies) between Halmeu and Piatra Neamţ has been calculated here.
Air line (approximately)
275 kilometers
149 nautical miles