Purpose. Formulation of the main factors affecting the internal migration of the population during the period of military aggression, creation of an economic-mathematical model that will reproduce the number of internally displaced persons (IDPs) for forecasting the financial support of macro-regions. Methodology. The research used general scientific and special research methods: the method of critical analysis, scientific abstraction and generalization of scientific experience of modern theoretical studies, methods of statistical analysis, expert evaluations, system-complex approach. Findings. The main differences in the reasons for the country citizens’ migration are identified in peacetime and in wartime. The factors that increase the behavioral uncertainty of displaced persons are outlined. It is proposed to create economic and mathematical models that will reproduce the dynamics of the number of displaced persons people to forecast the financial provision of macro-regions using the method of correlation-regression analysis. Invariable indicators that have the greatest impact on the number are determined for new arrivals in the specified territories. Originality. The economic and mathematical models presented in the article reproduce the dynamics of the number of internally displaced persons based on statistical data of a representative survey. Unlike the existing ones, they take into account the main factors that affect the internal migration of the population during the period of military aggression. Practical value. The economic-mathematical models presented in the article can be applied in practice in the methods for calculating the financial needs of regions, individual regions and settlements to forecast the number of forced migrants. The method proposed in the article for calculating the forecast quantity of internal migrants allows timely adjustment of the components of economic and mathematical models, which contributes to increasing their reliability.