 First element from Celtic *"duro-" 'fort'; in "Dūrobrīvae", Celtic *"brīwa" 'bridge'
Possibly derived from Brythonic *"iska", 'water, fish' and *"leith", 'damp, wet'.From Celtic *"iska" 'water' (Irish "uisce"); second element in "Isca Dumnoniorum" (Exeter) is a tribal name (see "Devon")
From Brythonic *"lēd-" [from Celtic *"leito-"] + *"rïd-" [from Celtic *"(φ)ritu-"] = "Grey Ford"
From Celtic *"lindo-" 'pool' + Latin "colonia" 'colony'
From Celtic *"mamm-" 'breast' (referring to the shape of a hill)
From Celtic *"nowijo-" 'new' (Welsh "newydd") + *"magos" 'field, plain'
From Brythonic *"penn-" 'hill, top, head, chief' (Welsh "pen") + possibly *"kelli" 'to stand' (Welsh "gelli")
From Brythonic *"penn-" 'hill, top, head, chief' (Welsh "pen") + *"koid-" 'wood' (Welsh "coed"), or *"cēd-" 'wood'
First element from Brythonic *"penn-" 'hill, top, head, chief' (Welsh "pen" 'head, end, chief, supreme') = Irish "ceann" 'head', from Proto-Celtic *"kwenno-"
From Brythonic *"penn-" 'hill' (Welsh "pen")
From English "lower" + Brythonic *"penn-" 'hill'
From Brythonic *"penn"- 'hill' and possibly p-Celtic *"carr" 'rocks'.This matches the earliest attestation from c. 1190, Pencher.