The calculated distance (air line) between Bonn and Bad Homburg vor der Höhe is approximately 76 miles respectively 122 kilometers.
By car or train, the actual journey to Bad Homburg vor der Höhe is certainly longer, as only the direct route (as the crow flies) between Bonn and Bad Homburg vor der Höhe has been calculated here.
Air line (approximately)
122 kilometers
66 nautical miles