View this artwork by appointment, at Tate Britain's Prints and Drawings Rooms
The subject was identified by Ian Warrell; the watermill stands on the north bank of the River Rother south of the village of Fittleworth, about three miles south-east of Petworth, but is much altered. It is also seen in a gouache and pen and ink drawing of the type usually associated with Turner’s 1827 visit to Petworth but perhaps a little earlier (Tate D24606; Turner Bequest CCLIX 41).1 In the present sketch there are barges on the river and an annotated detail of one at the lower right. The mill appears again on the verso and on folio 24 recto (D18748, D18749).
See Ian Warrell in Butlin, Luther and Warrell 1989, pp.118, 123 note 101.