Is there a mountain in wales called mount rouge or red mountain?

Yes. Mynydd Rhuddlan or Rhyd-y-Groes (literally meaning Red Mountain) is the highest point the Clwyd Range, situated north of the town of Ruthin, Denbighshire, north-east Wales. It is not to be confused with Mynydd Rhos-y-gwaliau (also called Rhyd-y-Groes) which is the highest hill of the Flintshire Range.