This research is the addition to the reconstruction of the ethnic map of the Mongolian Altai and Khubsugul after the Qing Dynasty (1911-1919). There were identified the ethnic ties between the Oirat, Khalkha and Khubsugul ethnic groups, also the ties of these groups with the Buryat habitat and the Turkic population in the South and Oriental Siberia. After 1915 the migrants began to appear in this region, in the west - the Kazakhs, Uighurs, Tuva, in the north-east - the Buryats. However, they have not affected the ethnic map of the region, because the Mongolian administrative system was represented by the Khoshuns and the Otokos. The situation has changed in the following decades, when the Kazakhs became massive penetration to the western regions of Mongolia. However, for a long period they didn't become the Mongolian citizens and weren't the official Mongolian ethnic group. As a result, the Buryats who migrated after 1915 out of Russia, had got the individual territory in Mongolia - 5 khoshuns in the east of the country. The Khubsugul region wasn't divided into the Khosuns, though some somons became almost the Buryat areas. In this regard, reconstruction of the ethnic map of this region according to this data will recreate the ethnic picture of the Mongolian Altai and the Khubsugul region without the Kazakhs' and Buryats' influence that happened later.