Buuxi weedha soo socota: Magaca ugu horeeya ee Irish ee goobta magaalada casriga ahi waxay ahayd, Old Irish for "oak wood of Calgach", ka dib jaahilka aan la aqoon. John Keys O'Doherty, oo ahaa Roman Catholic Bishop of Derry laga soo bilaabo 1889 ilaa 1907, wuxuu isku dayay inuu Calgach la mid dhigo Agricola's Calgacus, halka Patrick Weston Joyce uu leeyahay "Calgach", oo macnaheedu yahay "dagaalyahan adag", wuxuu ahaa magac la siiyay oo caadi ah. Macbad Celtic Christian ah ayaa la aasaasay qarnigii lixaad; Adomnán magacyada Saint Columba sida aasaasaha. Magaca waxaa loo beddelay "Daire Coluimb Chille", "oak wood of Columba", oo markii ugu horreysay lagu xusay Annals of Ulster ee 1121. Markii ay sii weynaatay meeshaas, magaca waxaa loo soo gaabiyay "Doire" (hadda waa la dhawaaqaa). Tan waxaa markii dambe loo beddelay "Derry". Sanadkii 1604, "Derrie" waxaa la siiyay jaartarkiisii ugu horreeyay ee boqortooyada oo ah magaalo iyo shirkad degmo oo uu siiyay James I oo reer England ah. Waxyaabaha
Deegaanka waxaa burburiyay 1608 Cahir O'Doherty, oo ahaa madax Irish ah oo ka tirsan Inishowen.