River Cain
{{Short description|River in north Powys, Wales}}
{{Use dmy dates|date=January 2018}}
{{Use British English|date=January 2018}}
{{Infobox river
| name = River Cain
| native_name = {{native name|cy|Afon Cain}}
| name_other =
| name_etymology =
| image = File:Cain bridge, Llanfechain - geograph.org.uk - 518983.jpg
| image_size =
| image_caption = Llanfechain Bridge over Afon Cain
| map =
| map_size =
| map_caption =
| pushpin_map = Wales Powys
| pushpin_map_size =
| pushpin_map_caption= Location of the mouth within Powys
| subdivision_type1 = Country
| subdivision_name1 = Wales
| subdivision_type2 =
| subdivision_name2 =
| subdivision_type3 = Counties
| subdivision_name3 = Powys
| subdivision_type4 =
| subdivision_name4 =
| subdivision_type5 =
| subdivision_name5 =
| length = {{convert|16|km|mi|abbr=on}}
| width_min =
| width_avg =
| width_max =
| depth_min =
| depth_avg =
| depth_max =
| discharge1_location=
| discharge1_min =
| discharge1_avg =
| discharge1_max =
| source1 = Confluence of Nant Alan and Nant Fyllon
| source1_location =
| source1_coordinates= {{coord|52.7706|-3.2837|display=inline}}
| source1_elevation =
| mouth =
| mouth_location = River Vyrnwy
| mouth_coordinates = {{coord|52.774|-3.147|display=inline,title}}
| mouth_elevation =
| progression =
| river_system =
| basin_size =
| tributaries_left = Nant Fyllon, River Abel, Nant Llys
| tributaries_right = Nant Alan, The Brogan
| custom_label =
| custom_data =
| extra =
}}
The River Cain (Afon Cain in Welsh) is a river in north Powys which flows into the River Vyrnwy.
Cain's source is just west of Llanfyllin, at the confluence of the Nant Alan and Nant Fyllon.{{cite web|title=Afon Cain - conf Nant Fyllon to conf The Brogan|url=http://environment.data.gov.uk/catchment-planning/WaterBody/GB109054049820|website=Environment Agency - Catchment Data Explorer|publisher=Environment Agency|accessdate=17 March 2016}}
After flowing east through Llanfyllin, where it is joined by the small River Abel, it continues eastwards alongside the A490 highway. It then turns north-east to pass through Llanfechain and is joined by the Nant Llys before finally flowing east again.{{cite web|title=Subcatchment:Afon Cain - conf The Brogan to conf Afon Vyrnwy|url=https://restorerivers.eu/wiki/index.php?title=Subcatchment%3AAfon_Cain_-_conf_The_Brogan_to_conf_Afon_Vyrnwy|website=Restoring Europe's Rivers|publisher=Environment Agency et al|accessdate=17 March 2016}} It is fed by the Brogan,{{cite web|title=The Brogan - source to conf Afon Cain|url=http://environment.data.gov.uk/catchment-planning/WaterBody/GB109054049780|website=Environment Agency - Catchment Data Explorer|publisher=Environment Agency|accessdate=17 March 2016}} before joining the Vyrnwy near Llansantffraid-ym-Mechain.{{cite web|title=Severn Upper and Cain River|url=http://environment.data.gov.uk/catchment-planning/OperationalCatchment/c054001d|website=Environment Agency - Catchment Data Explorer|publisher=Environment Agency|accessdate=23 April 2015}}
The Cain is 16 km long.{{cite web|title=Afon Cain|url=http://gb.geoview.info/afon_cain,37918076w|website=Geoview|accessdate=19 March 2016}}
File:Afon Cain south of Llanfechain - geograph.org.uk - 601546.jpg|Afon Cain south of Llanfechain
File:Bend 'n Cain - geograph.org.uk - 689687.jpg|Afon Cain between Llanfyllin and Llanfechain