The Bonasila River (Deg Xinag: Ngidegh Srixno') is a 125-mile (201 km) tributary of the Yukon River in the U.S. state of Alaska. It heads in the Nulato Hills and flows generally southeast to the Bonasila Slough, an anabranch of the larger river. The slough flows around the west side of Elkhorn Island, which is about 27 miles (43 km) northwest of Holy Cross, further downstream on the Yukon.