The aimag borders
Russia (
Zabaykalsky Krai) to the north. The neighbouring aimags are
Selenge to the northwest,
Töv to the west,
Govisümber to the southwest,
Dornogovi to the south,
Sükhbaatar to the southeast, and
Dornod to the east. The border with Töv is divided by the city of
Baganuur, an administrative exclave of
Ulaanbaatar. The northwest of the aimag is covered by the eastern part of the
Khentii Mountains; towards the southeast, the landscape changes into the eastern Mongolian steppe plains. The mountain
Burkhan Khaldun in the
Khan Khentii Strictly Protected Area is considered sacred and assumed to be the birthplace of
Genghis Khan. The
Kherlen River originates South of the Burkhan Khaldun; the river then crosses the south of the aimag in the eastern direction after a detour through Töv. A little further east is the spring of the
Onon River. The
Onon-Balj National Park is located in the northeast of the aimag. == Population ==