Keston Postmill was built in 1716. In December 1836 the Westerham millwright William Ashby fitted new sails and repaired the breast of the mill. It is currently Kent's oldest surviving windmill There is a date of 1716 carved on the main post. In its working days it had four double Patent sails as shown below carried on a cast iron windshaft.

The drawings below where prepared for a new book entitled.

'Windmills of North West Kent and Kentish London (and the men who built them)'   by Rob Cumming

I have never seen the mill so the drawings are based on dimensions and photos taken by Luke Bonwick in 2003, Rob’s photographs and from the Mills Archive Trust web site