The Rhymney River is a river located in South Wales, flowing through the county of Caerphilly and the city of Cardiff. It stretches approximately 30 miles (48 kilometers) and is known for its scenic beauty and historical significance. The river originates in the Brecon Beacons National Park and eventually joins the Bristol Channel. Historically, the Rhymney River played a vital role in the industrial development of the region, particularly during the Industrial Revolution. It served as a transportation route for coal and other goods, contributing to the growth of nearby towns. Today, the river is a popular spot for walking, fishing, and enjoying nature.