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near Winford, Somerset (between Winford and Chew Magna, to the south west of Bristol).
Thought to have been established c.1650, and by the 18th century had become the largest gunpowder-producing site in south west England. The works closed in the 1820s following the end of the Napoleonic wars, after which it became a farm, now known as Powdermills Farm. The intact buildings can be seen from a public road (see photos), but there is a complex of ruined buildings, weirs, and watercourses on private land, including a 250m long pond built to serve the waterwheels and also to provide a channel for boats for internal transport. For more detail, see the Historic England website
By the 1750s the mill was owned by a group of five Bristol merchants, including Jeremiah Ames (d.1776). In 1753 charcoal made from dogwood was brought in from Guildford. From 1751 to 1768 the accountant was William Dyer, who became a shareholder in 1763. 
1821 Advert: 'LITTLETON, near WINFORD, SOMERSET.
Valuable HAY, HORSES, WAGGONS, and other FARMING STOCK, also valuable SCREW-PRESSES, TIMBER, Manufacturing Implements, and Building Materials,
To be SOLD by AUCTION,
By S. OLIVER,
On the Premises, at the Gunpowder Manufactory, at Littleton, near Winford, Somerset, on MONDAY & TUESDAY NEXT, the 17th and 18th of September,
THE FARMING STOCK consists of seven mows of prime bay ; 2 good cart horses, ditto mare, two tilted waggons, one with iron axles, other with iron arms ; 1 coal ditto, with iron axles ; 1 tilted cart, with iron arms; 1 hay ditto, 1 light ditto, 1 powder ditto ; 2 broad-wheel puts, with iron arms ; timber carriage, with geer, blocks, chains, &c.; field-roller, drag, 4 pair of old wheels, 5 sets of horse-harness, set of bells, iron screw jacks, some of large dimensions sheep-rank, quantity of wheel and hand-barrows, step and rung ladders, with variety of other articles in the husbandry line.
Sundry Utensils, belonging to the Manufactory, comprising large iron screw presses; 1 four-wheel & 2 smaller water-engines; 3 large beams, scales, and weights ; 1 box, with triangle, beam, scales, and weights; a wheel-lathe and tools ; pump borer, with 6 bits ; pit and cross-cut saws; carpenter’s bench, chest, and tools ; oak timber trees; a quantity of dry oak, elm, ash, and deal plank, quarter, board, spokes, stocks, and fellies; 16 large mill chocks quantity of crab and yew-tree cogs and rounds; two grindstones; a level, with moulds, sweeps, &c.; blacksmith’s bellows, anvil, vice, &c.; a quantity of iron bars, large hammers, spanners. &c. ; a variety of large and small tubs, boxes, sieves, sieve and batter hoops and bottoms ; 8 large sashes for a cucumber frame a quantity old iron; a quantity of charcoal and sacks; 1 counting-house desk and stools ; an alarum dock, 1 table, 1 cupboard, a quantity of nails, 2 carriage beds, a faggot pile, railing logs, fire-wood. &c. ; various empty casks, with other articles, too numerous for insertion.
The Hay, Horses, Waggons, &c., with the Grass of the Farm, to be sold Monday, in lots. Sale to begin at 11 o'clock each day.'