Loughborough Inlet is one of the lesser principal inlets of the British Columbia Coast. It penetrates the Coast Mountains on the north side of the Discovery Islands archipelago, running about 35 km (22 mi) from its head at the mouth of the Stafford River to and Cordero Channel, which are on the north side of West Thurlow Island. A further 14 km (8.7 mi) west along Chancellor Channel is Johnstone Strait.