With the increase of people's need for energy, electrical energy transmission has become a very important issue as well as electrical power generation. One of the most important problems in energy transmission is finding the best route in a very complex study area. To date, many people from different disciplines have come together to find the best routes by manual methods like using paper maps and deciding which route is the least-cost path (LCP) to the destination point. Today it is known that, in engineering problems, and especially in path-finding or site-placing problems, the Geographic Information System (GIS) is the most powerful tool. On the other hand, as finding the best route is a very complicated problem and many criteria should be considered, including slope, landslide, road/railway/pipeline crossing, ice zones, distances to roads, national parks, archaeological areas, residential areas forests, and river crossings, multicriteria decision methods like the analytic hierarchy process (AHP) and fuzzy analytic hierarchy process (FAHP) should be used to make the most accurate decisions. In this study, the AHP and FAHP are used to weight criteria relevant to energy transmission line (ETL) routing. According to the criteria, digital maps of the sample study area are edited, weighted, converted to raster-based format, and gathered using the Environmental Systems Research Institute's ArcGIS Desktop 10 software. After generation of the weighted surface map, the LCP tool is used to find the best route. By selecting different start and end points in the sample study area, accuracy and performance of the best routes according to the LCP algorithm are assessed and some problems of the routes for ETL routing are presented. With this study, mistakes by manual methods will decrease in ETL routing and other routing problems.