Sewardstone is actually in the county of Essex - in Epping Forest District since 1974. Its postcode though is E4 - the only London postal area which stretches beyond the boundaries of Greater London itself.

The area consists of scattered development with large sections of open land. The King George V Reservoir forms the boundary with the London Borough of Enfield to the west and a section of woodland forms the boundary with the London Borough of Waltham Forest to the south. Sewardstone itself is largely devoted to nurseries and market gardening.

The world HQ of the Scout movement, Gilwell Park, is at Sewardstone.

Sewardstone was first mentioned by name in 1177, when Henry II granted land there and in Epping to the canons of Waltham.

In 1278 Robert de Vere, Earl of Oxford, claimed Sewardstone as the right of his wife Alice, daughter of Gilbert de Sandford. He asserted that in the time of Henry II, the manor was held by a certain Adam, Alice's great-great-grandfather. The Abbot of Waltham successfully opposed this claim by producing his royal charters, and Sewardstone remained part of the abbey's demesne until the Dissolution. It was treated as a separate estate and from the 13th century had its own manor court.

In 1547 the king granted Sewardstone to Sir Ralph Sadler, who in the same year conveyed it to Sir Anthony Denny. It passed on to descendants until the death, in 1660, of James Hay, Earl of Carlisle. His executors, who included William Russell, Earl (later Duke) of Bedford, sold it in 1665 to William Pocock from whom it was purchased in 1674 by James Sotheby.

The Sotheby family held Sewardstone for over two centuries.