River Terrig

{{Short description|River in north-east Wales}}

{{Use dmy dates|date=January 2018}}

{{Use British English|date=January 2018}}

{{Infobox river

| name = Terrig

| native_name ={{native name|cy|Afon Terrig}}

| name_other =

| name_etymology = From Welsh terydd, "swift", or terig, "violent, harsh"

| image = Afon Terrig - geograph.org.uk - 691389.jpg

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| image_caption = The Terrig near Leeswood Old Hall.

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| subdivision_type1 = Country

| subdivision_name1 = Wales

| subdivision_type2 =

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| subdivision_type3 = Counties

| subdivision_name3 = Denbighshire, Flintshire

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| source1 =

| source1_location = Llyn Cyfynwy, near Graianrhyd, Denbighshire

| source1_coordinates= {{coord|53|4|58.28|N|3|10|13.49|W|display=inline}}

| source1_elevation = {{convert|370|m|abbr=on}}

| mouth =

| mouth_location = confluence with River Alyn, Flintshire

| mouth_coordinates = {{coord|53|8|56.929|N|3|6|1.595|W|display=inline,title}}

| mouth_elevation = {{convert|95|m|abbr=on}}

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The River Terrig ({{langx|cy|Afon Terrig}}) is a small river in north-east Wales.

The river rises at Llyn Cyfynwy near Graianrhyd village in the community of Llanarmon-yn-Ial, Denbighshire, about three miles from the source of the River Alyn.Cambridge County Geographies: Flintshire, Cambridge University Press, p.25 It then flows northwards and eastwards, forming the boundary between the old parishes of Nercwys and Treuddyn. At Nant-y-Mynydd it is joined by several small springs from Mynydd Ddu, and finally itself joins the River Alyn at Pontblyddyn, Flintshire.

The Terrig is a habitat for brown trout. Its name is derived from its rapid flow after times of heavy rain; Thomas Pennant, in his Tours in Wales, described it as "the Terrig, or the violent, [...] often of a tremendous swell and fury".Pennant, T. Tours in Wales, Volume 2, Wilkie and Robinson, 1810, p.44