Salix polaris, the polar willow, is a species of willow with a circumpolar distribution in the high arctic tundra, extending north to the limits of land, and south of the Arctic in the mountains of Norway, the northern Ural Mountains, the northern Altay Mountains, Kamchatka, and British Columbia, Canada.

[1][2][3][4] One of the smallest willows in the world, it is a prostrate, creeping dwarf shrub, only 2–9 cm (0.79–3.54 in) high, and has underground branches or runners in the uppermost soil layers.

The long runners with freely rooting stems creep in mats of mosses and lichens, which keeps them together and protects them from the wind.

[1][2][5] Fossil remains of the species from the Pleistocene ice ages are known in Europe south to southern England, the Alps, and the Carpathians.

[3] The species has also been reported from Arizona,[3][4] but this is not accepted by the USDA.