This article discusses in a simplified manner how to use the multiple functions of the Geographic Information System (GIS) to support the engineering decision for vital and important sites that require the decision-maker to have a high degree of certainty, such as the decision related to choosing the best location for the airport among several sites. This paper aims to provide a practical model that allows for a decision support system on how to adopt a GIS software by both its part Arc-Map and Arc-Catalog combined with analytic hierarchy process (AHP) method to make strategic decisions by spatial and non-spatial analysis to choose the appropriate site for the project as those related to choosing an airport location. Nineteenth criteria were considered to analyze the study area which is represented by three governorates of the middle Euphrates region in Iraq, Babil, Kerbala, and AL-Najaf. Finally, the research presented a practical and efficient approach for the decision maker to select the appropriate location for the airport based on the value of the highest suitability index.