Officially designated as a river,[1] the Widden Brook rises on the Great Dividing Range, southwest of Nullo Mountain. The river flows generally southeast and north northeast, joined by five minor tributaries including the Blackwater Creek, before reaching its confluence with the Goulburn River about 5 kilometres (3.1 mi) east northeast of the village of Kerrabee.[1] Widden Brook descends 901 metres (2,956 ft) over its 61 metres (200 ft) course.[2]