Wellbrook Beetling Mill is a National Trust property about 6 kilometres west of Cookstown on the Ballinderry River, and the last working beetling mill in Northern Ireland. Beetling was the process of pounding woven linen cloth with heavy mechanical hammers — beetles — to flatten and smooth it, giving finished linen its characteristic sheen. The mill's water-powered machinery, driven by a large external waterwheel, has been restored to working order and visitors can see and hear it in operation.
The mill dates from the late 18th century and operated commercially until 1968. The National Trust acquired it shortly afterwards and restored the machinery. The site includes a small exhibition on the Ulster linen industry and the mill's working history. The surrounding glen and the walk along the Ballinderry River are attractive in their own right.
Opening is seasonal — typically April to October — and guided demonstrations of the working machinery run at weekends and on public holidays. Admission is charged for non-National Trust members. The mill is one of the most distinctive industrial heritage sites in this part of Northern Ireland.