The Swan River stretches 72 kilometres from the Darling Scarp to the Indian Ocean, its tidal estuary carving through the centre of Perth and forming the natural boundary that shaped European settlement from 1829. Captain James Stirling chose the river's southern shore for the Swan River Colony, and by the 1850s Barrack Street Jetty had become the city's principal landing point for passengers and goods arriving by water. The jetty's name derives from the military barracks that once stood at the foot of Barrack Street, demolished in 1966 to make way for the Mitchell Freeway but memorialised in the Barracks Arch that still frames the northern end of St Georges Terrace. Today the river defines Perth's geography as decisively as it did two centuries ago. The South Perth foreshore, Kings Park escarpment, and Elizabeth Quay waterfront all orient themselves toward the water, and the city's evening skyline reads clearest from a vessel moving downstream past the narrowing channel. A swan river dinner cruise tour departs twice weekly from Pier 3 at Barrack Street Jetty, the same mooring point that once received wool bales and timber shipments bound for London. The three-hour voyage tracks a loop through Perth Water, the wide basin enclosed by the Causeway and Narrows Bridge, where black swans — the species that gave the river its English name in 1697 — gather in rafts near the shallows. The river's width varies from 70 metres at Walyunga National Park to more than a kilometre at Melville Water, but the urban section between the city and Fremantle holds a consistent depth of four to seven metres, maintained by the Swan River Trust since 1988. Evening light on the water shifts with the season: summer twilight stretches past 20:00, casting long shadows from the high-rises along Riverside Drive, while winter sailings depart into full darkness. The working port of Fremantle lies 19 kilometres downstream, but dinner cruises hold to the sheltered upper estuary, where the current runs weak and the fetch remains short. Navigation lights mark the channel between moored yachts and the limestone breakwaters that edge Point Belches and Pelican Point, remnants of 19th-century efforts to stabilise the river mouth against southwesterly swells.