Rheged (ˈr̥ɛɡɛd) was one of the kingdoms of the Hen Ogledd ("Old North"), the Brittonic-speaking region of what is now Northern England and southern Scotland, during the post-Roman era and Early Middle Ages. It is recorded in several poetic and bardic sources, although its borders are not described in any of them. A recent archaeological discovery suggests that its stronghold was located in what is now Galloway in Scotland rather than, as was previously speculated, being in Cumbria. Rheged possibly extended into Lancashire and other parts of northern England. In some sources, Rheged is intimately associated with the king Urien Rheged and his family. Its inhabitants spoke Cumbric, a Brittonic dialect closely related to Old Welsh.
The origin of the name Rheged has been described as "problematic". One Brittonic-language solution is that the name may be a compound of rö-, a prefix meaning "great", and cę:d meaning "wood, forest" (c.f. Welsh coed) although the expected form in Welsh would be *Rhygoed. If association of the name with cę:d is correct, the prefix may be rag-, meaning "before, adjacent to, opposite". Derivation from the element reg, which with the suffix -ed has connotations of "generosity", is another possibility.
The name Rheged appears regularly as an epithet of Urien (a late 6th-century king of Rheged) in a number of early Welsh poems and royal genealogies. His victories over the Anglian chieftains of Bernicia in the second half of the 6th century are recorded by Nennius and celebrated by the bard Taliesin, who calls him "Ruler of Rheged". He is thus placed squarely in the North of Britain and perhaps specifically in Westmorland when referred to as "Ruler of Llwyfenydd" (identified with the Lyvennet Valley). Later legend associates Urien with the city of Carlisle (the Roman Luguvalium), only twenty-five miles away; Higham suggests that Rheged was "broadly conterminous with the earlier Civitas Carvetiorum, the Roman administrative unit based on Carlisle".