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Ock
Bridge across the River Ock as it flows into the Thames at Abingdon
Location
Country	England
Counties	Oxfordshire
Towns	Abingdon-on-Thames
Physical characteristics
Source
• location	Little Coxwell, White Horse Hills
Mouth	River Thames
• location	Abingdon-on-Thames, Oxfordshire
Length	34 km (21 mi)
Discharge
• location	Abingdon-on-Thames
• average	1.52 m3/s (54 cu ft/s)
• minimum	0.11 m3/s (3.9 cu ft/s)23 August 1976
• maximum	15.8 m3/s (560 cu ft/s)6 March 1972

The River Ock is a small English river which is a tributary of the River Thames. It has as its catchment area the Vale of White Horse, a low-lying and wide valley in south Oxfordshire, and flows into the River Thames, at Abingdon on the reach above Culham Lock.

The River Ock rises near the village of Little Coxwell. It collects tributaries from each village along the base of the White Horse Hills, where springs emanating from the chalk hills allowed settlements to flourish in former times. Among these tributaries is the Osse Stream, rising in Cumnor.^{[citation needed]}

From Little Coxwell, the Ock runs around Longcot and flows past Stanford in the Vale, where it is about 10 feet (3 m) wide. The name of Stanford comes from stony ford, possibly alluding to the Ock crossing at Stanford Mill. Thence it runs past Charney Bassett, Lyford, Garford and Marcham Mill, before losing its identity and its waters to the Thames at Abingdon by the old Hygienic Laundry building. An iron bridge crosses at the junction which was built by the Wilts & Berks Canal Company. This gives the erroneous impression that the Ock is that canal, but in fact the original canal entrance a few yards downstream is now blocked up. This has been replaced under a restoration project by a newer entrance closer to Culham Lock.^{[citation needed]}

The soils through which the River Ock flows are the Jurassic sedimentary series (Greensands, Gault, Kimmeridge Clay and corallian limestone), while some of its tributaries arise in chalk springs. Until recent times, native crayfish and many freshwater fish species inhabited the river. Increased housing in the Vale, with the resultant surface drainage, may have threatened these species but surveys have not yet been performed in the 21st century.^{[citation needed]}

Although normally placid, the Ock can flood low-lying areas of south Abingdon after persistent heavy rainfall; this recently occurred in April 2023,^[1] January 2024^[2], September 2024^[3] and November 2024 ^[4].

The hydronym Ock appears to be derived from a Celtic word for 'salmon'.^[5]

• Tributaries of the River Thames
• List of rivers of England

51°40′N 1°17′W / 51.667°N 1.283°W / 51.667; -1.283