The River Conwy (; ) is a river in northern Wales. From its source to its discharge in Conwy Bay it is long and drains an area of 678 square km. "Conwy" was formerly anglicised as "Conway." The name 'Conwy' derives from the old Welsh words cyn (chief) and gwy (water), the river being originally called the 'Cynwy'. It rises on the Migneint moor where a number of small streams flow into Llyn Conwy, then flows in a generally northern direction, being joined by the tributaries of the rivers Machno and Afon Lledr before reaching Betws-y-Coed, where it is also joined by Llugwy. From Betws-y-Coed the river continues to flow north through Llanrwst, Trefriw (where it is joined by the Afon Crafnant) and Dolgarrog (where it is joined by Afon Porth-llwyd and Afon Ddu) before reaching Conwy Bay at Conwy. A local quay, Cei Cae Gwyn, is located on its bank. During spring tides the river is tidal as far as Tan-lan, near Llanrwst. Tributaries of the River Conwy This is a list of named tributaries of the Conwy (and their tributaries) listed from source to sea; River Machno at Conwy Falls Afon Lledr near Betws-y-coed River Llugwy at Betws-y-coed Afon Gallt y Gwg Nant y Goron at Llanrwst Afon Crafnant & Fairy Falls at Trefriw River Geirionydd Afon Ddu (1) at Dolgarrog Afon Porth-llwyd at Dolgarrog Afon Dulyn at Tal-y-bont Afon Ddu (2) Afon Garreg-wen Ffrwd Cerriguniawn Afon Melynllyn Afon Hiraethlyn near Tal-y-cafn Afon Roe near Llanbedr-y-Cennin Afon Tafolog Afon Gyffin at Conwy Geology and geomorphology The Conwy is bounded to the east by the rolling ancient mudstone hills of the Silurian period, the Migneint Moors. These acid rocks are generally covered in thin, often acid soils and for large parts of the upland areas the cover is of moor grass — Mollinia spp and Erica communities. As a result, the water entering the river tends to be acidic and often coloured brown with humic acids. To the west, the catchment is underlain by older Cambrian rocks which are harder and the landscape is, as a consequence, more dramatic with high craggy hills and mountains, through which the river falls in cascades and waterfalls. Examples of torrential river geomorphology can be seen at Conwy Falls and in the Lledr Gorge. The land to the east is highly forested with planted non-native conifers. On the western side of the valley