The River Trent is one of the major rivers of England. Its source is in Staffordshire between Biddulph and Biddulph Moor. It flows through the Midlands (forming a once-significant boundary between the North and South of England) until it joins the River Ouse at Trent Falls to form the Humber Estuary, which empties into the North Sea below Hull and Immingham.
The name "Trent" comes from a Celtic word possibly meaning "strongly flooding". More specifically, the name may be a contraction of two Celtic words, tros ("over") and hynt ("way"). This may indeed indicate a river that is prone to flooding. However, a more likely explanation may be that it was considered to be a river that could be crossed principally by means of fords, i.e. the river flowed over major road routes. This may explain the presence of the Celtic element rid (c.f. Welsh rhyd, "ford") in various placenames along the Trent, such as Hill Ridware, as well as the Saxon‐derived ford. Another translation is given as "the trespasser", referring to the waters flooding over the land.
It is unusual amongst English rivers in that it flows north (for the second half of its route), and is also unusual in exhibiting a tidal bore, the "Aegir". The area drained by the river includes most of the northern Midlands.
In 1711, Lord Paget leased his rights to George Hayne, who carried out improvements, quickly opening the river to Burton. He monopolised freight, causing discontent among merchants and encouraging interloping. His business was continued as the 'Burton Boat Company', but after the opening of the Trent and Mersey Canal, the Boat Company were unable to compete. Eventually in 1805, they reached an agreement with Henshall & Co. the leading canal carriers for the closure of the river above Wilden Ferry. Though the river is no doubt legally still navigable above Shardlow, it is probable that the agreement marks the end of the use of that stretch of the river as a commercial navigation.
The first improvement of the lower river was the Newark cut which, by means of two locks, brought the navigation into the town centre in 1772-3 and by-passed Averham weir, without closing it for navigation.
At the beginning of the 1790s, William Jessop was employed to make proposals for navigation between Shardlow and Gainsborough and made his second report in 1793. This proposed a cut and lock at Cranfleet near Long Eaton opposite the mouth of the Soar, a cut and lock at Beeston to join the Nottingham Canal, being built at the same time, and another at Holme Pierrepoint with the aim of increasing the minimum depth from to . This was authorized by Act of Parliament in 1794 and the work finished by 1801.
Down river of Shardlow, the non-tidal river is navigable as far as the Cromwell Lock near Newark, except just west of Nottingham where there are two lengths of canal, the Cranfleet and Nottingham. Below Cromwell lock, the Trent is tidal, and therefore only navigable by experienced, well-equipped, and well-informed boaters. This is especially true at Trent Falls, a lonely spot where the Trent joins the Yorkshire Ouse, to form the Humber estuary. The timetables of flows and tides of the two rivers and the estuary are very complex here, and vary through the lunar cycle. Boats coming down the Trent on an ebbing tide often have to beach themselves (sometimes in the dark) at Trent Falls to wait for the next incoming tide to carry them up the Ouse.
At certain times of the year, the lower tidal reaches of the Trent experience a moderately large tidal bore (up to five feet (1.5m) high), commonly known as the Trent Aegir; taking its name from the Norse god of the ocean. The Aegir occurs when a high spring tide meets the downstream flow of the river, the funnel shape of the river mouth exaggerates this effect, causing a large wave to travel upstream as far as Gainsborough, Lincolnshire, and sometimes beyond. The aegir cannot travel much beyond Gainsborough as the shape of the river reduces the aegir to little more than a ripple, and weirs north of Newark-on-Trent, Nottinghamshire stop its path completely. It is also alleged that King Cnut (Canute) performed his purposely unsuccessful attempt to turn the tide back in the River Trent at Gainsborough; if this is the case it is highly probable that the tide Cnut attempted to turn was the Aegir.