The calculated distance (air line) between Unterseen and Zürich (Kreis 3) is approximately 56 miles respectively 90 kilometers.
By car or train, the actual journey to Zürich (Kreis 3) is certainly longer, as only the direct route (as the crow flies) between Unterseen and Zürich (Kreis 3) has been calculated here.
Air line (approximately)
90 kilometers
48 nautical miles