An econometric model using time series analysis techniques is employed to model and forecast population changes in Doña Ana County, New Mexico. The model focuses on the interplay between economic and demographic variables. Individual, cointegrated equations are generated to account for the components of population change - births, deaths, net domestic and net international migration. Birth and death equations prove easier to model because of stable changes from period to period in relation to income levels and national demographic trends. Net migration equations were more difficult to model as economic conditions, specifically labor market conditions, influence changes over time. Predefined exogenous variables are used to generate out-of-sample simulations for the individual components of population change. Using those results, total population projections are estimated until the year 2018. Doña Ana County is projected to witness a slowdown in population growth, primarily as a consequence of increased domestic out-migration