The calculated distance (air line) between Oer-Erkenschwick and Wuppertal is approximately 27 miles respectively 44 kilometers.
By car or train, the actual journey to Wuppertal is certainly longer, as only the direct route (as the crow flies) between Oer-Erkenschwick and Wuppertal has been calculated here.
Air line (approximately)
44 kilometers
24 nautical miles