Solva Woollen Mill claims to be the oldest working woollen mill in Pembrokeshire. There were 26 woollen mills in Pembrokeshire in 1900. Today Solva Woollen Mill is one of the two remaining woollen mills in the county.
In 1907 Tom Griffiths moved his mill from St Davids to a new purpose-built building in Middle Mill powered by a 10 feet (3.0 m) diameter overshot water wheel. Equipment included machinery to process the fleece, several small powered looms, a hand loom for making stair carpets and a flannel press. At first the cloth was finished at a nearby fulling mill, but later the mill installed its own fulling machine. The mill made tweeds, blankets, flannel, stair carpets and knitting wool. Prime Minister Ramsay MacDonald had a Middle Mill tweed suit made in 1929.
The waterwheel was restored in 2007. There were plans to restore the drive wheel and line shaft, and to generate electricity. The original mill building was restored in 2011 and now holds the shop and tea room. The mill today specializes in making flat woven rugs and runners. Their rugs are sold in the United Kingdom, Japan, the US and Australia. The Prince of Wales and Duchess of Cornwall have visited the Solva Woollen Mill and used rugs from the mill in furnishing their property at Llwynywermod.