The Ustya is a river in Kotlassky, Krasnoborsky, Ustyansky, and Velsky Districts of Arkhangelsk Oblast in Russia. A very short portion of the river also forms the boundary between Kotlassky District and Velikoustyuzhsky District of Vologda Oblast. It is a right tributary of the Vaga River. The length of the river is . The area of its basin . Its main tributaries are the Kizema River and the Kokshenga River (both left). The name of Ustyansky District originates from the Ustya River.