Protected areas are the geographic areas defined and managed by laws to ensure long-term conservation of ecosystem services and cultural values with nature, and it is of great importance for future generations to access pristine natural resources. Uludag National Park has rich ecosystem efficiency in terms of plant and animal biodiversity, endemic plant species, carbon storage capacity, snow cover and water potential. For this reason, protected area boundary and size are important for the holistic protection of water and natural resources. In this study, the landscape inventory of Uludag National Park was determined by Geographical Information Sys-tems (GIS) and the potential watershed boundaries were determined by ArcHydro Watershed analysis. As a result of the study, the difference between the actual and potential basin areas is estimated to be approximately 11.20 ha. The protected area serves a qualified mission to ensure that natural resources are sustained for the future generations in a fair and protected manner when the basin borders are considered as an integrated boundary that feeds the hydrological cycle.