The calculated distance (air line) between Canillo and La Seu d'Urgell is approximately 16 miles respectively 26 kilometers.
By car or train, the actual journey to La Seu d'Urgell is certainly longer, as only the direct route (as the crow flies) between Canillo and La Seu d'Urgell has been calculated here.
Air line (approximately)
26 kilometers
14 nautical miles