The calculated distance (air line) between Zürich (Kreis 6) / Unterstrass and Riehen is approximately 43 miles respectively 70 kilometers.
By car or train, the actual journey to Riehen is certainly longer, as only the direct route (as the crow flies) between Zürich (Kreis 6) / Unterstrass and Riehen has been calculated here.
Air line (approximately)
70 kilometers
38 nautical miles