The calculated distance (air line) between Oer-Erkenschwick and Düsseldorf is approximately 36 miles respectively 58 kilometers.
By car or train, the actual journey to Düsseldorf is certainly longer, as only the direct route (as the crow flies) between Oer-Erkenschwick and Düsseldorf has been calculated here.
Air line (approximately)
58 kilometers
31 nautical miles