In communities governed by customary law, the position of the land is crucial, so it is important to take care of any land that has been granted usage rights to its residents. The research objective is to analyze the concept of abandoned land in customary law communities as a foundation for national land law. The type of research used is normative legal research using secondary data to be further analyzed descriptively qualitatively. The results of the research show that the emphasis on abandoned land criteria in customary law is more on the length of time the land is not used, so that the physical land becomes unmaintained, as if it is no man's land. If the obligation to maintain and use the land is not fulfilled properly, accompanied by sanctions against some indigenous peoples, the party who neglects the land for some time will no longer be given management rights over customary land, even if they submit an application to the customary institution again. Meanwhile, customary lands that have been abandoned and returned to the control of the alliance are then used by customary institutions either by giving them to members of the customary law community or external parties who meet the requirements of the customary law community. The concept of abandoned land that exists in customary law is normalized in national land law, requiring that a new area of land rights can be declared abandoned if there is an element of intent. Even this is not instantaneous because through a series of processes to identify the land that was allegedly deliberately abandoned until the government issued a stipulation of the land as abandoned land.