The Afon Tywi (River Towy) is one of Wales's most celebrated and storied rivers, stretching approximately 120 kilometres (75 miles) through some of the most breathtaking countryside in the country. Rising on the lower slopes of Crug Gynan in the Cambrian Mountains — within 15 kilometres of the source of the River Teifi — the Tywi flows generally south-westwards through Carmarthenshire, passing through the market towns of Llandovery and Llandeilo before emptying into the Irish Sea southwest of Carmarthen. Fed by numerous tributaries including the Cothi, Gwili, Brân, and Doethie, the river drains a vast upland catchment and is widely regarded as one of the finest sea trout rivers in the entire United Kingdom. Its reputation for producing double-figure sewin (the Welsh name for sea trout) is unmatched — the Tywi is thought to produce more sea trout exceeding 10 pounds than any other river in Britain, with fish recorded to over 20 pounds. The Tywi Valley is a Special Area of Conservation (SAC), reflecting the river's extraordinary ecological importance and the quality of its waters.