The River Tywi is the longest river in Wales, stretching approximately 75 miles (120 kilometers). It flows through the picturesque Carmarthenshire region, starting in the Brecon Beacons National Park and emptying into Carmarthen Bay. The river is known for its scenic beauty and rich biodiversity, making it a popular spot for fishing and outdoor activities. The Tywi is significant for its historical and cultural importance, as it has been a vital waterway since ancient times. It passes through several towns, including Llandeilo and Carmarthen, and is home to various wildlife species, contributing to the area's natural heritage.