The River Og is a short river in Wiltshire

Wiltshire

Wiltshire is a ceremonial county in South West England. It is landlocked and borders the counties of Dorset, Somerset, Hampshire, Gloucestershire, Oxfordshire and Berkshire. It contains the unitary authority of Swindon and covers...

, 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...

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It rises near the hamlet of Draycot Foliat

Draycot Foliat

Draycot Foliat is an hamlet in Wiltshire, England, on the back road between Chiseldon to the north and Ogbourne St. George to the south. The nearest major town is Swindon which is about north. The most notable feature is probably the small Airstrip with its model helicopter instruction centre...

, and flows south through Ogbourne St George, Ogbourne St Andrew and Ogbourne Maizey

Ogbourne Maizey

Ogbourne Maizey is a hamlet in Wiltshire. It is at the Marlborough end of the village of Ogbourne St. Andrew. The hamlet on the banks of the River Og is dominated by commuter housing and race horse stables on the narrow road that leads over the downs to Rockley. Local primary-level children usually...

 to Marlborough, where it joins the River Kennet

River Kennet

The Kennet is a river in the south of England, and a tributary of the River Thames. The lower reaches of the river are navigable to river craft and are known as the Kennet Navigation, which, together with the Avon Navigation, the Kennet and Avon Canal and the Thames, links the cities of Bristol...

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The river flows through a gap in the Marlborough Downs which creates a natural transport route, now followed by the A346 and once used by the Midland and South Western Junction Railway

Midland and South Western Junction Railway

The Midland and South Western Junction Railway was, until the 1923 Grouping, an independent railway built to form a north-south link between the Midland and London and South Western Railways allowing the Midland and other companies' trains to reach the port of Southampton.-Formation:The M&SWJR...

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The name is a back-formation

Back-formation

In etymology, back-formation is the process of creating a new lexeme, usually by removing actual or supposed affixes. The resulting neologism is called a back-formation, a term coined by James Murray in 1889...

from Ogbourne (which itself means Occa's stream).