Rubuta ci gaba don wannan sakin layi - Segovellauni ya zauna a kwarin kogin Rhône, kudu da kogin Isère da yammacin Vercors Massif, kusa da garin Valence na yanzu. Wannan ƙasar, daidai da yankin Valentinois na zamani, Polybius da Livy sun kira shi 'Tsibirin' a cikin bayanin da suka yi game da ƙetare Hannibal na Alps
a cikin 218 BC, domin yana tsakanin Rhône da Isère, kusa da haɗuwa da koguna biyu. A kudu, yankinsu ya faɗaɗa zuwa Kogin Drôme, ko wataƙila kudu zuwa filayen Montélimar. Wataƙila ya shafi yankin Vivarais da ke yammacin Rhône, tsakanin kogin Eyrieux da kogin.