Zhangjiakou, also known also by several other names, is a prefecture-level city in northwestern Hebei province, bordering Beijing to the southeast, Inner Mongolia to the north and west and Shanxi to the southwest. Its administrative area has a population of 4.35 million, and covers 36,947 square kilometres. The urban area of Zhangjiakou is divided into Qiaoxi and Qiaodong Districts which have 473,193 inhabitants in 2010, but the prefecture-level city is much larger, spanning around 36,800 square kilometres. Due to its position on several important transport arteries, it is a critical transport node for travel between Hebei and Inner Mongolia and connecting northwest China, Mongolia, and Beijing.