Sewardstone is a hamlet in the parish of Waltham Abbey, in the Epping Forest District of Essex, England.

It is located south of the main built-up area of Waltham Abbey, lying between Epping Forest, Chingford and Enfield.

[1] Settlement at Sewardstone could date back to the Iron Age, indicated by the discovery of a dugout canoe.

The King George V Reservoir and Sewardstone Marsh form the boundary with the London Borough of Enfield, to the west.

To the south of the hamlet, London Buses Route 215 offers a frequent service from Lee Valley Camp Site to Walthamstow Central.