The Tatshenshini River (/ˌtætʃɛnˈʃini/; Tlingit Tʼachanshahéeni, Southern Tutchone Shäwshe Chù) is a river in the southwestern Yukon and the northwestern corner of British Columbia, Canada. It originates in British Columbia, near Haines Highway. It flows north into Yukon, then it turns west and south before it returns into British Columbia, where it flows through the Tatshenshini-Alsek Provincial Wilderness Park. There it joins the Alsek River, which then flows in the Pacific Ocean in Alaska, U.S..