Buck Ait is an island in the River Thames

River Thames

The River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...

 in Oxfordshire

Oxfordshire

Oxfordshire is a county in the South East region of England, bordering on Warwickshire and Northamptonshire , Buckinghamshire , Berkshire , Wiltshire and Gloucestershire ....

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. It is on the reach above Shiplake Lock

Shiplake Lock

Shiplake Lock is a lock and weir situated on the River Thames in England near the village of Shiplake, Oxfordshire. It is just above the points where the River Loddon joins the Thames and Shiplake Railway Bridge crosses the river...

 near Sonning

Sonning

Sonning, occasionally called Sonning-on-Thames is a village and civil parish in the Borough of Wokingham in the English county of Berkshire, a few miles east of Reading. The village is situated on the River Thames and was described by Jerome K...

.

The island is uninhabited and tree covered but sits opposite houses with extensive river frontages. The island shows the effect of soil movement, with the upstream end almost joined to the bank, and the downstream end broken into smaller islets.

The island derives its name from the eel buck

Eel buck

Eel bucks are a type of fish trap that was prevalent in the River Thames in England up to the 20th century. It was used particularly to catch eels which were a staple part of the London diet....

s or traps that used to be placed here. There were reports in the late 19th century that they caused comsiderable hindrance to navigation. There were also eel bucks in St Patrick's Stream

St Patrick's Stream

St Patrick's Stream or Patrick Stream is a backwater of the River Thames in England, which flows into the River Loddon near Wargrave, Berkshire. It leaves the Thames on the reach above Shiplake Lock near Buck Ait, downstream of Sonning....

 on the bank opposite upstream. This stream is believed to have been a tributary stream of the River Loddon

River Loddon

The River Loddon is a river in the English counties of Berkshire and Hampshire. It is a tributary of the River Thames, rising within the urban area of Basingstoke and flowing to meet the Thames near the village of Wargrave...

which became an outfall when the water level was raised by the building of Shiplake Lock.

Buck Ait is positioned towards the Oxfordshire bank of the river.