The calculated distance (air line) between Osterholz-Scharmbeck and Dortmund is approximately 131 miles respectively 211 kilometers.
By car or train, the actual journey to Dortmund is certainly longer, as only the direct route (as the crow flies) between Osterholz-Scharmbeck and Dortmund has been calculated here.
Air line (approximately)
211 kilometers
114 nautical miles