A map display system and method are provided. The display system includes a map information acquiring unit that acquires map information and a congestion level acquiring unit that acquires a congestion level for each road section within the map. The system also includes a route line display determining unit that determines whether a route line is displayed superimposed on any road line, the route line representing a planned travel route, each road line representing a road section within the map. The display is controlled such that if the route line is displayed superimposed on any road line a congestion line is displayed at a position by a first off-set distance from the road line on the display part and if the route line is not displayed superimposed on any road line, the congestion line is displayed at a second off-set distance from the road line on the display part.