River Usk River Usk The River Usk (; ) rises on the northern slopes of the Black Mountain ("y Mynydd Du"), Wales, in the westernmost part of the Brecon Beacons National Park. Initially forming the boundary between Carmarthenshire and Powys, it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and Abergavenny after which it takes a more southerly course. Beyond the eponymous town of Usk it passes the Roman legionary fortress of Caerleon to flow through the heart of the city of Newport and into the Severn estuary at Uskmouth beyond
Christina River into New Castle County in Delaware, where it flows through western and southern areas of the city of Newark and then turns northeastwardly, passing the town of Newport and approaching Wilmington from the southwest. It receives White Clay Creek from the west near Newport, and Brandywine Creek in Wilmington, approximately 2 miles (3 km) upstream of its mouth. The Christina River and its tributaries drain an area of 565 square miles (1,463 km²). Brandywine Creek, despite being considered a "tributary" of the Christina, drains 58% of this area (325 mi²/842 km²). White Clay Creek and its tributary, Red Clay Creek,