River Irthing

The River Irthing is a river in Cumbria, England and a major tributary of the River Eden. The name is recorded as Ard or Arden in early references. For the first 15 miles of its course it defines the border between Northumberland and Cumbria.
The name Irthing may be of Brittonic origin, though its precise etymology is uncertain. The last part of the name is from –ïnn, an adjectival and, in place-names, toponymic suffix, added to nouns or adjectives. The first part may be arth, meaning "a bear" . Or else, the first part of the name could either one of two elements suffixed with -ed, an early Celtic nominal suffix meaning "having the quality of..". The first of these is, *ar, an ancient river-naming element implying either horizontal motion, "flowing", or else "rising" or "springing up" . The second possibility is *īr, meaning "fresh, clean, pure".

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