The calculated distance (air line) between Nieder-Ingelheim and Taunusstein is approximately 12 miles respectively 20 kilometers.
By car or train, the actual journey to Taunusstein is certainly longer, as only the direct route (as the crow flies) between Nieder-Ingelheim and Taunusstein has been calculated here.
Air line (approximately)
20 kilometers
11 nautical miles