It rises at East Meon then flows 34 km (21 mi) in a generally southerly direction to empty into the Solent at Hill Head near Stubbington.

It flows due north, then northwest to West Meon, and southwest to Warnford followed by its characteristic, quite straight, south-southwest course, with many tiny wobbles in short stretches.

The river descends through the villages of Exton, Corhampton and Meonstoke, Droxford, Wickham, and Titchfield.

The river outflows over 2 miles (3.2 km) of estuary through the marshes of the Titchfield Haven National Nature Reserve to enter the Solent through a small harbour at Hill Head.

There are several components that are used to determine this, including biological status, which looks at the quantity and varieties of invertebrates, angiosperms and fish.