The province's total land area indicates that its topography ranges from level to rugged terrain. The western portion of Bulacan for instance has been classified in the Landscape Map as belonging to the lowland category with an approximate coverage of close to 50 percent of the provincial land area. On the other hand, the eastern part of the province covers those areas that are hilly to mountainous. This is where the province interfaces with the southeastern part of Luzon. In the middle of these two major landforms are the piedmont landscapes, which have elevation of about 50 to 100 meters above sea level. Over one half of Bulacan's overall land area have been classified as having slopes less than 8 percent or those considered as having level to gently sloping terrain and this is found on the western part of Bulacan.