Between 1925 – 1929, approximately 12 non-native mountain goats (Oreamnos americanus) were translocated from Alaska and British Columbia to the foothills of the Olympic Range, USA. By 1970, descendants of these goats had colonized the entire Olympic Range and concerns about the management of this introduced species developed as damage to alpine soil and vegetation occurred. A series of removals reduced the population from 1,175 in 1983 to 389 goats by 1990, followed by a period a stasis and growth indicated again in 2011 and 2016. We used empirical demographic and genetic data to parameterize a population genetics individual-based simulation model of the Olympic Range mountain goat population. We calibrated the model to simulate the population trajectory for Olympic mountain goats from establishment in 1925 through the 1983 census, and validated model dynamics by simulating the period from 1990 to 2016. Modeled population dispersal closely tracked anecdotal reports. However, observed heterozygosity did not align with published research, suggesting a process not accounted for within the simulation model, such as a bottleneck, founder effect, or population trajectory dynamics. Sensitivity analyses showed that changes in annual reproductive rate had the greatest influence on population trajectories, followed by juvenile mortality and adult female mortality, respectively. The modeled population showed that approximately 80% of the total animals removed during the 1980’s needed to be female in order for the observed population stasis to occur. This model has the potential to be used more widely with established or introduced mountain goat populations in other regions.