Abstract: Border areas are special in terms of governance as the spontaneous cross-border population shift in such areas is closely related to the logic of governance of a country. This paper is a field study of H County, Yunnan Province, a county neighboring Vietnam. In addition to a variety of categories of spontaneous cross-border population shift, this study identifies some outstanding characteristics in terms of direction, scale and legitimacy of said population shift. Such population shift has dual effects on social order of the border areas of a country. On the one hand, it is a bridge that can help communication between the two countries for mutual benefit and, on the other hand, it presents challenges to governance of the border areas, especially at some special moments, such as during the pandemic years when public health security was top priority for governance. For governance in areas of high spontaneous cross-border population mobility, it is, therefore, necessary that certain techniques be applied to maintaining a balance between aforesaid dual effects for the benefits of the two neighboring peoples.

Key words: border, spontaneous cross-border population shift, bridge, security