This study investigated changes in population dynamics and paddy holdings over three generations in two villages established by the Lao people in a basin in northern Laos. In the study area, government policy has promoted migration from mountainous areas since the 1970s. However, there was limited land for new paddy reclamation in the basin, and therefore many residents who migrated from mountainous areas, mainly Khmu people, had limited opportunities to engage in wet-rice cultivation in the basin villages where they resided and ultimately continued the subsistence swidden agriculture they had practiced in the mountainous areas. The common method of acquiring new paddies in basin villages, where it is difficult to develop new paddies, is to purchase paddies from residents who have moved away from the villages. Many residents waited for such opportunities and worked in urban areas to make money to purchase paddies. Migrants from mountainous areas in these basin villages are faced with the choice of staying in the basin, where paddy fields are scarce, or migrating to urban areas. We found that the basin villages functioned as intermediate points for migration between mountainous and urban areas.