This paper proposes a two-phase framework to predict the impact dispersion area of a reentering space object. A semi-analytic approach is developed that predicts the dispersion area by combining an analytic impact point sensitivity model with corrections to account for aerodynamic drag. The first phase of the framework (preparation phase) generates a database storing the coefficients used in the correction model; this applies the least-squares method to the results of numerical experiments on the space object reentry for various initial states (position and velocity) and aerodynamic characteristics (i.e., ballistic coefficient). The second phase (execution phase: during the reentry event) predicts the dispersion area of the falling object using the correction coefficients database generated in the preparation phase. The validity and computational efficiency of the proposed method are demonstrated through a case study.