The boundary of real property is the fundamental element for securing rights attached to land. Countries, even with a long-standing cadastral tradition, often face the challenge of interpreting the course of a parcel boundary on the ground based on the available evidence, as data quality is very heterogeneous. Various cadastral principles and procedures have been developed for the determination of parcel boundaries in the field, which may also be associated with resolving boundary disputes. This article documents and compares the principles and procedures applied in the determination of property boundaries in selected civil law countries based on a novel conceptual model developed for that purpose. The notion of ‘boundary determination’ used in this article refers to demarcating and surveying land parcel boundaries during the initial cadastral survey and cadastral update procedures. The selected countries include Denmark and Sweden, which apply Nordic civil law; Slovenia and Turkey, which apply German civil law; and Spain, which applies Napoleonic civil law. The demarcation principles and processes applied in the different cadastral systems, the parties involved, and the evidence taken into consideration in these processes are described and compared. The main aim is to contribute to the documentation of the reasoning applied to the property boundary determination in the selected civil law countries.