Characteristics of urban system of regional structure are: size of settlements, their spatial distribution, and their functions. Despite rapid development in Egypt, suffecient studies of the development patterns of its territories have not been sufficiently achieved or covered. Like other regions of the Nile valley in Egypt, Northern Upper Egypt region (NUE) was characterized by its natural, social, and economic homogeneity for long periods of time. But the accelerated development that has given rise to new axes of movement has revealed imbalances in a pattern that has not been analitacally studied to help guide current and future development processes. Thus, this research focuses on analyzing size distribution (as the most important element of the structure). The aim of this paper, therefore, is to analyse the size distribution of urban system in the northern oblasts in terms of: the change in the size, proportions and growth rates of urban agglomerations over the past 40 years, the change in their grade and size distribution, followed by a change in their urban dominance. To achieve this, the paper reviews a theoretical review of methods for analysing urban styles/systems size distribution. The paper then examines an analysis of the size distribution of northern regions using some theoretical and applied measures (Primate City law, Size-Rank Distribution, Urban Primacy Index). The research concludes a set of findings and recommendations that may help to understand the size distribution of the northern region as one of its most important characteristics.