Lewis & Short

Sisăpo, ōnis, f., a small town in Hispania Baetica, rich in mines of cinnabar, now Almaden in the Sierra Morena, Plin. 3, 1, 3, § 14; Cic. Phil. 2, 19, 48.
Hence, Sisăpōnensis, e, adj., of or belonging to Sisapo, Sisaponian: regio, Plin. 33, 7, 40, § 121: minarii, id. 33, 7, 40, § 121.