The calculated distance (air line) between Sant Celoni and L'Hospitalet de Llobregat is approximately 30 miles respectively 49 kilometers.
By car or train, the actual journey to L'Hospitalet de Llobregat is certainly longer, as only the direct route (as the crow flies) between Sant Celoni and L'Hospitalet de Llobregat has been calculated here.
Air line (approximately)
49 kilometers
26 nautical miles