Wulai sits along the Nanshih River, which springs from Lake Sungluo in the Hsuehshan Range, between Mt. Tsuntoumu and Mt. Tsulan. After flowing through Happen, Fushan, Hsinhsien, Wulai, and Chungchi, it runs out of Wulai Township and into Hsintien City, where it merges with the Peishih River, becoming the Hsintien River.
烏來鄉屬於南勢溪流域，南勢溪源自雪山山脈主脊棲蘭山與拳頭母山之間的松蘿湖，流經哈盆、福山、信賢、烏來、忠治後出烏來鄉境，在新店市和北勢溪交會後匯成新店溪。