Bristol Harbour is the harbour in the city of Bristol, England. The harbour covers an area of 70acre. It has existed since the 13th century but was developed into its current form in the early 19th century by installing lock gates on a tidal stretch of the River Avon in the centre of the city and providing a tidal by-pass for the river. It is often called the Floating Harbour as the water level remains constant and it is not affected by the state of the tide on the river.
Netham Lock in east Bristol is the upstream limit of the harbour. Beyond the lock is a junction: on one arm the navigable River Avon continues upstream to Bath, and on the other arm is the tidal River Avon. The first 1mi of the floating harbour, downstream from Netham Lock to Totterdown Basin, is an artificial canal known as the Feeder Canal, while the tidal River Avon follows its original route. Downstream of Totterdown Basin, the floating harbour occupies the former natural course of the River Avon, whilst the tidal River Avon flows through an artificial channel known as the New Cut. This separation of the floating harbour and the tidal River Avon allows boats in the harbour to remain floating at low tide, reduces currents and silting and prevents flooding.
Between Bristol Temple Meads railway station and Hotwells, the harbour and the River Avon run parallel at a distance of no more than 0.65mi apart. Downstream of Bristol Temple Meads railway station, the floating harbour meanders through Bristol city centre, Canon's Marsh and Hotwells. At Hotwells, the floating harbour rejoins the tidal River Avon, via a series of locks, and flows into the Avon Gorge.