Tukulan (Russian: Тукуланы; Yakut: Тукулаан) are relief forms shaped by aeolian processes of the Central Yakutian Lowland, Yakutia, Russian Federation. They are sand dunes of a characteristic type mainly found along the valley of the Lena River, in the area of the lower Vilyuy river. Tukulan come in the form of isolated dunes, but also as large sand-covered areas in certain spots of the plain, often among the trees of the taiga. The largest of the dunes lies at 65°08′01.6″N 122°58′00.7″E / 65.133778°N 122.966861°E near the Linde River and reaches almost 40 kilometres (25 mi) in length.