Selection of bridge construction sites over rivers is one of the most important tasks in construction feasibility studies. In this paper, potential sites for the construction of a river bridge are ranked for suitability using analytical hierarchy process for a river in the northern part of Iran. Fuzzy logic is used to incorporate the uncertainty associated with decision making into the model. Geographic information system is used to facilitate the decision-making process by determining alternative sites and evaluating the selection criteria. A floodplain is determined by the river reach using a hydraulic simulation. This is done to identify the length and height of potential bridges for each site. Two scenarios are analyzed in this paper: the first ranks bridge construction sites regardless of the location of an existing bridge and the second ranks bridge construction sites considering the existing bridge. The result of this analysis shows that the existing bridge is one of the best locations but not the best one.