The Eaton River successively crosses the municipalities of Saint-Isidore-d'Auckland, Newport, Sawyerville, Cookshire-Eaton and East Angus.

The main neighboring hydrographic slopes of the Eaton River are: Many streams and different branches of the river originate near the crest of the northern White Mountains and meet on the flanks near the Quebec border and New Hampshire.

Its watershed is 642 kilometres (398.92 mi) its drop is 396 metres (1,299 ft).

[1] The small valley at the head of the Eaton River (located in Quebec) is a continuation of the valley of the "West Branch" of the Indian Stream flowing south into New Hampshire to go to discharge into the river Connecticut.

The toponym "Eaton River" was made official on December 5, 1968, at the Commission de toponymie du Québec.