Elgi River (Russian: Эльги) is a river in Yakutia in Russia, a left tributary of the Indigirka River. It is formed by the confluence of the Degdega and Kao Rivers. The length of the Elgi is 394 kilometres (245 mi). The area of its drainage basin is 68,200 km². The Elgi freezes up in October and remains icebound until late May - early June.