The Yuan dynasty was a vast empire founded by Mongol leader Kublai Khan in China. During its existence, its territory was divided into the Central Region (腹裏) governed by the Central Secretariat (Zhongshu Sheng) and places under control of various provinces (行省) or Branch Secretariats (行中書省), as well as the region under the Bureau of Buddhist and Tibetan Affairs (Xuanzheng Yuan). In addition, the Yuan emperors held nominal suzerainty over the western Mongol khanates, but in reality none of them were governed by the Yuan dynasty due to the division of the Mongol Empire.
The most important part of the Yuan Empire was the Central Region, which covered the region of the Yuan capital Khanbaliq (Dadu, modern Beijing). The Central Region consisted of present-day Hebei, Shandong, Shanxi, the south-eastern part of present-day Inner Mongolia and the Henan areas to the north of the Yellow River. Since it was considered the most important region of the dynasty, it was directly governed by the Zhongshu Sheng at Khanbaliq; similarly, another top-level administrative department called the Bureau of Buddhist and Tibetan Affairs (or Xuanzheng Yuan) held administrative rule over Tibet.
Branch Secretariats (行中書省), or simply provinces (行省), were provincial-level administrative organizations or institutions subordinated to the Zhongshu Sheng, though they were not exactly provinces in modern sense. There were 11 "regular" provinces in Yuan dynasty.