[1] It runs 12.2 miles (19.6 km) from its source at Flitcham to the River Great Ouse at Wootton Marshes where it terminates.

From the lake the river runs through a wooded valley out of the Park and into the countryside south of the royal estate of Sandringham.

The river continues westward skirting the northern edge of a large Forestry Commission plantation and south of Sandringham.

In the fields on the other side of the bridge was the deserted medieval village of Babingley; the ruins of the Church of St Felix can be seen.

In the hamlet of Babingley, near the river, Felix of Burgundy is said to have landed c.630 AD to introduce Christianity to East Anglia.