Spatial boundaries of real estate are a very important issue in the context of the discussions on the multidimensional cadastre. The precise determination of the extent of property rights in 3D space is driven by the dynamic development of urban planning, architecture and construction. It is becoming more and more popular to design modern buildings above or below other structures or the ground. The reason for such solutions is often limited land resources, especially in highly urbanised areas. Currently, Polish law defines in detail the procedures for demarcating property boundaries exclusively on the ground, i.e. in 2D. Both the definitions of the boundaries, the limit points, and the methods of their designation in various modes, which enable the boundaries to be determined according to the legal status, are specified. The rules for determining the extent of ownership and other property rights are currently set out in the Polish legislation in the rank of acts and regulations. They follow the Roman principle of superficies solo cedit, which means that what is on the surface belongs to the land. The intention for the implementation of the 3D cadastre is to move away from this principle. The purpose of this paper is to examine the guidelines concerning the spatial (3D) extent of ownership and other property rights contained in the Polish legislation in force at present. The aim of the publication is to answer the question of whether there are any specific indications of the extent of ownership above and below the ground regulated by special regulations.