Alian Township is located on the northeast side of the Kaohsiung Plain at east longitude 120.1923/north latitude22.5303. It is situated on the north end of the western territory of Kaohsiung County, in between Erren River and Agongdian River. It borders Dagang Mountain and Tianliao Township to the east, in the west with Lujhu Township, in the north with Erren River and Guanmiao Township of Tainan County and Gueiren Township, and in the south with Gangshan Town.