(mod. Usellus), an ancient town of Sardinia, situated in the hills to the S.E. of Oristano, 900 ft. above sea-level. A bronze tablet of A.D. 158 (a tabula patronatus, setting forth that M. Aristius Balbinus had accepted the position of patron of the town for himself and his heirs) speaks of the place as Colonia Julia Augusta Uselis. From this it would seem that it had become a colony under Augustus, were it not that Pliny (H.N. iii. 85) asserts that Tunis Libisonis was the only colony in Sardinia at his time. It may be that civic rights were obtained from Augustus (Th. Mommsen in Corp. Inscr. Lat. x. p. 816). The site of the ancient town is marked by the church of S. Reparata, and various antiquities have been found there. The episcopal see was transferred to Ales in the 12th century, though the old name is still officially used.