The Kel Ajjer are the Tuareg confederation of the Tassili n'Ajjer plateau and its surrounding ergs, on the borders of southeastern Algeria and southwestern Libya. The plateau itself takes its name from them: Tasili n Ajjer, "the plateau of the Ajjer."
Their language is Tamahaq, in the same northern Tuareg branch as the Kel Ahaggar. The traditional seat of the Amenokal was at Ghat, on the Libyan side of the modern border; Djanet on the Algerian side is the principal contemporary town.
The Kel Ajjer historically commanded the trans-Saharan route between Ghat and Kano via Bilma, and their political fortunes long mirrored those of the Ottoman governors of Tripoli and the Italian colonial administration of Libya, with whom successive Amenokals negotiated tribute and passage.
The plateau's prehistoric rock art — among the densest concentrations on earth — is conventionally subdivided into Round Head, Bovidian, Equidian, and Cameline periods spanning twelve thousand years; the Kel Ajjer are the present custodians of the world heritage landscape. The confederation maintains close kinship and political ties with the Kel Ahaggar to the west and the Kel Aïr to the south.