The calculated distance (air line) between Bad Sooden-Allendorf and Dortmund is approximately 109 miles respectively 176 kilometers.
By car or train, the actual journey to Dortmund is certainly longer, as only the direct route (as the crow flies) between Bad Sooden-Allendorf and Dortmund has been calculated here.
Air line (approximately)
176 kilometers
95 nautical miles