The name Llanddeusant means the church with two saints. The village lies close to the Alaw river, which supplies the power for two historic mills, Melin Llynnon, or Llynnon Mill, and Melin Howell, or Howell Mill.

Llynnon Mill, Llanddeusant

Llynnon Mill dates from 1776, and is the only working wind-powered mill in Wales. The Mill is open during the holiday season, and visitors may sample the stone-ground flour that is produced here in the adjacent Mill shop and tea room.

Howell Mill, Llanddeusant

Howell Mill was built in 1817, and restored in 1975. It is in private ownership, but access is occasionally permitted to some parts of the mill.