Yuen Long , formerly Un Long, is an area and town located in the northwest of Hong Kong, on the Yuen Long Plain. To its west lie Hung Shui Kiu and Ha Tsuen, to the south Shap Pat Heung and Tai Tong, to the east Au Tau and Kam Tin, and to the north Nam Sang Wai. The central part of Yuen Long was traditionally a market town in the area now known as Yuen Long San Hui , in Yuen Long District in the New Territories in Hong Kong. The site of the market town was situated centrally with regard to surrounding villages, allowing villagers a convenient location to sell their crops and fish. The market is a place to allow people from villages in northwest New Territories to shop and trade. Like many market towns in Hong Kong, the market operates only on certain days each week.