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
First River settlers of Newark in the 17th century. From 1863 to 1890 the brook was culvertised and now flows underground through two culverts, each high by wide until discharging into the Passaic. The brook once flowed through, and now flows under, what is now Branch Brook Park in the city of Newark. First River The First River, in the state of New Jersey in the United States, is a subterranean river and the first main tributary of the Passaic River encountered while travelling upstream from its mouth at Newark Bay. Beginning at the confluence of Mill Brook and Branch Brook (near