52.571°N 3.039°W / 52.571; -3.039

The River Onny is a river in Shropshire, England. It is a major tributary of the River Teme.

The river's name derives from Welsh and means the river on which ash trees (Welsh: onnau) grew.^[1]

The river has its sources in the Shropshire Hills at White Grit,^[2] located in Mid and South-west Shropshire. It has two branches, the East Onny and West Onny, which converge at Eaton, to the east of Lydham. The River Onny then flows in a south-easterly direction, through Craven Arms and Onibury (a village it gives its name to),^[1] before it finally has its confluence with the River Teme just upstream of Ludlow at Bromfield.^[3] From White Grit to Bromfield, the river flows over a distance of 25 miles (40 km).^[4][5]

The River Teme is itself a tributary of the River Severn, converging just south of Worcester city centre. The River Severn then flows south-west meeting the sea at Bristol Channel.^[6]

Geologically, the Onny has the type section just west of Craven Arms of the Caradoc series of the Ordovician system and there is a trilobite genus Onnia which was first defined here.^[7]