Usk is an unincorporated community in Pend Oreille County, Washington, United States. Usk is located along the Pend Oreille River 2 miles southeast of Cusick. Usk has a post office with ZIP code 99180. It is near the Kalispel Indian Reservation. There is also a general store.Usk was named for the River Usk in Wales around 1890.