The calculated distance (air line) between Amersham on the Hill and Hemel Hempstead is approximately 9 miles respectively 14 kilometers.
By car or train, the actual journey to Hemel Hempstead is certainly longer, as only the direct route (as the crow flies) between Amersham on the Hill and Hemel Hempstead has been calculated here.
Air line (approximately)
14 kilometers
8 nautical miles