Yuen Long , formerly Un Long, is an area and town on the Yuen Long Plain located in the New Territories West, Hong Kong. To its west lie Hung Shui Kiu (洪水橋) and Ha Tsuen, to the south Shap Pat Heung and Tai Tong, to the east Au Tau and Kam Tin (錦田), and to the north Nam Sang Wai.