The cultural stronghold of Celtiberians was the northern area of the central "meseta" in the upper valleys of the Tagus and Douro east to the "Iberus" (Ebro) river, in the modern provinces of Soria, Guadalajara, Saragossa and Teruel.
Arheologa Martín Almagro Gorbea in Alvarado Lorrio sta ugotovila, da so se značilna železna orodja in razširjena družinska socialna struktura razvite keltiberske kulture razvili iz arhaične kulture kastrov, za katero domnevata, da je bila prakeltska.