Shaanxi is geographically divided into three parts, namely Northern, Central and Southern Shaanxi. Northern Shaanxi (or "Shaanbei") makes up the southeastern portion of the Ordos Basin, and mainly comprises the two prefectural cities of Yulin and Yan'an on the northern Loess Plateau, demarcated from the Ordos Desert and the grasslands of Inner Mongolia's Ordos City by the Ming Great Wall. Central Shaanxi (or "Shaanzhong") is also known as the Guanzhong region, and comprises the drainage basin of lower Wei River east of Mount Long and north of the Qinling Mountains, where the majority of Shaanxi's population reside. Southern Shaanxi (or "Shaannan") comprises the three prefectural cities in the edge of the historical Bashu region south of the Qinling Mountains, and includes the three mountainous cities of Hanzhong, Ankang and Shangluo. Along with areas of adjacent Shanxi and Henan provinces, it formed the cradle of Chinese civilization.