Llansawel stands on two tributaries of the Cothi: – the Marlais and the Melinddwr or Mill Water, formerly known as the Livy. The parish has quite a colourful history.
Old Llansawel was built on dairy, beef and sheep farming. Because of its five roads, coming in from all directions, it was ideally placed to be a livestock market, on which it thrived for several centuries. Only the non-arrival of the railway in Victorian times prevented it from growing into a market town like Llandovery or Lampeter