Délin Chú is the Northern Tutchone name for the Teslin River, meaning "water running out from the lake." It is a major tributary of the Yukon River, originating in the Cassiar Land District of northwestern British Columbia and flowing northwest through Teslin Lake before continuing into southern Yukon, where it joins the Yukon River. The river's total length is approximately 632 kilometres, with a drainage basin of roughly 35,500 square kilometres.

The river is generally characterized as a wide, fast-moving, and deep waterway rated Class I-II, making it particularly well-suited for novice canoeists. The current is described as fast enough to cover significant distances without demanding technical skill, while remaining manageable for those still developing paddling technique. The typical put-in for paddling trips is at Johnson's Crossing on the Alaska Highway, where a 447-metre cantilever bridge crosses the river at kilometre 1296. This access point is straightforward by road. Trips commonly continue onto the Yukon River, with routes covering more than 350 kilometres through the southern Yukon, finishing near Little Salmon.

Notable features along the route include the confluence with the Mary River, Roaring Bull Rapids, and the historic site of Hootalinqua, which served as a river stop and supply point during the Klondike Gold Rush and was previously a First Nations fish camp and gathering place. A deteriorating gold rush-era paddle wheeler can be found on the shoreline near Hootalinqua. Moose are frequently spotted along the shorelines and are sometimes seen swimming the river.

Fishing regulations apply to the Teslin River (Délin Chú). From July 1 to October 15, only single-pointed barbless hooks with a gap of less than 20 mm are permitted. The river appears in Yukon government fishing regulation documents under both its Indigenous name and its anglicized name.

The river holds considerable historical and cultural significance. The Northern Tutchone people have long used it as a travel and fishing corridor. During the Klondike Gold Rush, it served as a secondary route to the gold fields, favoured by those seeking to avoid the Chilkoot Trail and the hazardous White Horse Rapids. Commercial activity on the river continued into the 1940s before it returned largely to its natural state.