The calculated distance (air line) between Bottrop and Castrop-Rauxel is approximately 17 miles respectively 27 kilometers.
By car or train, the actual journey to Castrop-Rauxel is certainly longer, as only the direct route (as the crow flies) between Bottrop and Castrop-Rauxel has been calculated here.
Air line (approximately)
27 kilometers
14 nautical miles