River Dhoo
{{Short description|River on the Isle of Man}}
{{Use British English|date=August 2023}}
{{Use dmy dates|date=April 2022}}
{{Unreferenced|date=December 2009}}
{{Infobox river
| name = River Dhoo
| native_name ={{native name|gv|Awin Doo}}
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| subdivision_type1 = Country
| subdivision_name1 = Isle of Man
| subdivision_type2 =
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| subdivision_type5 = Cities
| subdivision_name5 = Douglas, Union Mills, Crosby
| length_km = 10.5
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| source1 = Archallagan Plantation
| source1_location =
| source1_coordinates= {{coord|54.179|N|4.602|W|display=inline}}
| source1_elevation = {{convert|160|m|abbr=on}}
| mouth = Confluence with River Glass
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| mouth_coordinates = {{coord|54.151|N|4.502|W|display=inline,title}}
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| tributaries_left = Greeba River
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The River Dhoo ({{langx|gv|Awin Doo}}) is a river on the Isle of Man. The river rises in Marown and flows east towards Douglas through the central valley of the island, passing Crosby and Union Mills before meeting with the River Glass on the outskirts of Douglas where it flows out to sea through Douglas Harbour. The Dhoo (meaning black or dark in Manx) and the Glass (meaning clear or green) converge to form the River Douglas. It has a length of approx. {{convert|10.5|km|mi|abbr=on|order=flip}}.
More recent research{{when|date=May 2016}} suggests that the name is one of the oldest place-names in the island and comes from the early Celtic term 'duboglassio’ meaning 'black/dark stream'. This is a common name throughout the British Isles and is Dulas in Wales and Dawlish in England.{{citation needed|date=May 2016}}