- Securing natural habitats into which reintroduced species are released and those into which they will radiate is essential for the long-term establishment and viability of reintroduced populations. Consequently, the ability to project future range expansion is critical in reintroduction programs. We evaluated whether numerical growth and spatial expansion of a reintroduced population can be projected based on short-term monitoring of a newly reintroduced population, by studying a Persian fallow deer (Dama mesopotamica) population reintroduced to Israel. Over a five-year period, five to six adult (>1 yr) females were released semi-annually, for a total of 53 over the research period. We developed an individual-based spatially explicit model that projected spatial expansion of the female population in the wild. Model parameters were derived from empirical studies on movement patterns, home range establishment, behavioral adjustments, and demographic dynamics of reintroduced females during the first three years of the reintroduction project. Significant factors that were found to affect home-range establishment and that were incorporated into the model were: occurrence of Mediterranean woodland; occurrence of moderate terrain; roads; built-up areas; and presence of conspecifics. We tested the model by comparing its projections with field observations at the end of the five-year period since the project's onset, i.e., two years beyond the time on which parameters were based. The model was able to predict the direction and rate of expansion of the population and the main activity areas in the wild during the last two years. By using the model for long-term projection, future potential activity centers and landscape connectivity, important for securing the lands required for the Persian fallow deer future radiation, can be identified.