The purpose of this research is to present an optimum model for route location considering access to all the main points of the roads, passing compulsory points and having the minimum total cost. It is assumed in this research that the involved areas are level or rolling. The major capability of such models is predicting protected areas in an optimal corridor route location. In this paper, after describing the fulfilled studies in the field of road alignment, two mathematical models for alignment in level areas are presented. In the first model the forbidden zones are not considered, but in the second model the forbidden zones are prevented from being passed through by modeling these zones in a circular shape. In this research the mathematical non-linear programming has been used for modeling.