Avonmouth is a port and outer suburb of Bristol, England, facing two rivers: the reinforced north bank of the final stage of the Avon which rises at sources in Wiltshire, Gloucestershire and Somerset; and the eastern shore of the Severn Estuary. Strategically the area has been and remains an important part of the region's maritime economy particularly for larger vessels for the unloading and exporting of heavier goods as well as in industry including warehousing, light industry, electrical power and sanitation. The area contains a junction of and is connected to the south by the M5 motorway and other roads, railway tracks and paths to the north, south-east and east. The council ward of Avonmouth and Lawrence Weston is as drawn a simplified name as it includes Shirehampton and the western end of Lawrence Weston. Avonmouth is approximately rectangular, its length favouring the Severn shore and sits on the same bank as the city centre from which it lies west-north-west – at the mouth of the River Avon and on the eastern shore of the dredged, at this point highly saline Severn Estuary. Both rivers in shallow valleys by this stage have been defensively embanked primarily to allow the construction of the large port Avonmouth Docks which occupies most of the western part. The related Royal Portbury Dock is across the Avon (in Easton-in-Gordano). Avonmouth is home to chemical manufacturing plants, and north of the Avonmouth Docks is the gas-fired Seabank Power Station. Its light industrial and warehouse companies include Nisbets. Its long-established residential area in Avonmouth is between the industrialised zone and the M5 motorway, uniquely for Bristol west of the M5 motorway. Avonmouth Bridge of the M5 motorway forms the connection with Somerset, specifically with Easton-in-Gordano. The Wales-connecting M49 motorway runs between the M5 near Avonmouth and the M4 motorway at the Second Severn Crossing. The old Severn Bridge and the M48 motorway are linked to Avonmouth by the A403.