The area, covering 171 square kilometres, is mostly mountainous, with the Fushih Mountains to the north, the Ayu Mountains to the south, and the Peishih River meandering through it. Most of the population of more than 6000 is concentrated here in the river's small floodplain.
河谷平原分佈溪流兩岸，為坪林鄉之主要人口聚集地，全鄉總人口約六千餘人，面積一七一平方公里。