The calculated distance (air line) between Bochum and Oer-Erkenschwick is approximately 11 miles respectively 18 kilometers.
By car or train, the actual journey to Oer-Erkenschwick is certainly longer, as only the direct route (as the crow flies) between Bochum and Oer-Erkenschwick has been calculated here.
Air line (approximately)
18 kilometers
10 nautical miles