Northern River is a 1914–15 oil painting by Canadian painter Tom Thomson. The work was inspired by a sketch completed over the same winter, possibly in Algonquin Park. The completed canvas is large, measuring 115.1 × 102.0 cm. Painted over the winter of 1914–15, it was completed in Thomson's shack behind the Studio Building in Toronto. The painting was produced as he was entering the peak of his short art career and is considered one of his most notable works. In 1915 it was purchased by the National Gallery of Canada in Ottawa and has remained in the collection ever since.

Thomas John Thomson was a Canadian artist active in the early 20th century. During his short career, he produced roughly 400 oil sketches on small wood panels and approximately 50 larger works on canvas. His works consist almost entirely of landscapes, depicting trees, skies, lakes, and rivers. He used broad brush strokes and a liberal application of paint to capture the beauty and colour of the Ontario landscape. Thomson's accidental death by drowning at 39 shortly before the founding of the Group of Seven is seen as a tragedy for Canadian art.