The calculated distance (air line) between Dortmund and Jemeppe-sur-Sambre is approximately 142 miles respectively 228 kilometers.
By car or train, the actual journey to Jemeppe-sur-Sambre is certainly longer, as only the direct route (as the crow flies) between Dortmund and Jemeppe-sur-Sambre has been calculated here.
Air line (approximately)
228 kilometers
123 nautical miles