The calculated distance (air line) between Pematangsiantar and Kuala Selangor is approximately 153 miles respectively 246 kilometers.
By car or train, the actual journey to Kuala Selangor is certainly longer, as only the direct route (as the crow flies) between Pematangsiantar and Kuala Selangor has been calculated here.
Air line (approximately)
246 kilometers
133 nautical miles