Dornod aimag is located in broad hilly steppe in eastern Mongolian and, is elevated at 560-1,300m above the sea level. This wide steppe is surrounded by the branch mountains of Khentii mountains that Ar Ereen, Daguur Hills and Khyangan range mountains. There are eye-widening steppes as such Menen, Tamsag and Matad in the northern part. The aimag borders with Russian Chita region at the north, with Inner Mongolian Khulunbuir and Khyangan provinces at the southeast, with Tumentsogt, Sukhbaatar and Erdenetsagaan sums of Sukhbaatar aimag and Khentii aimag at the west and southwest respectively. The lowest point of Mongolia - Khukh Nuur hollow (556m AMSL) is in this aimag. Besides, rocks and stones from paleozoic, jurassic and cretaceous era and neogon moraine are widely found in this area.

The 241-260 days of the year are sunny and bright and precipitate about 150-300mm annually. In winter, average temperature is -27°С while in summer it is +21°C. Khalkhgol sum of Dornod gets the most precipitation since western wind stream barely affects the eastern side of Mongolia. In summer, well-known Musson wind stream brings chilly and humid air from ocean making the aimag the most precipitated area with unique nature. However, the extremely cold, tough winter comes with much snow. The territory around Numrug and Khalkhgol river is the only area that has maritime climate in summer and Siberian cold climate in winter. In Numrug mountains that is a branch of Khyangan mountain, the annual precipitation is 400-500mm. In the center of the aimag, Choibalsan sum, average air temperature is +0.4°C. In January it is -21.3°С, while in July it is +19.9°С with annual precipitation of 246mm and average wind speed of 4.1m/sec.

Since plain steppe dominates the whole aimag, the area has dry steppe-light brown soil, gobi-brown soil and it is rich in grazing plants. Khalkhgol, Onon, Ulz river basin is covered in black, black-brown soil, forest areas are covered in forest-black brown soil. Small sand dunes can be seen along Khalkhgol river basin and meadow-brown soil covers the eastern part of the aimag.

Rivers and Lakes in Dornod belong to Pacific ocean basin, and 128 rivers with total of 3,060km length, 173 lakes and over 300 springs are officially recorded in Dornod aimag. Rivers: Kherlen river initiated at Khentii mountains (1,090km), Onon (292km), Teel, Duch, Yamalkh, Khalkhgol river initiated at Khyangan mountains, Numrug, Degee, Orshuun, Galtastai and Altan river. Large and small lakes: Buir, Yakhi, Khukh, Sum, Baruun Shavart, Bayan Erkhet, Shavart, Shorvog, Jirmiin Tsagaan, Bor Davst, Bulgan Shavar, Galuut, Duruu, Chukh, Guntsengeleg and Galt. The beauty of Dornod, Buir lake is 615km², 50m deep and elevated at 583m above sea level. There are many other springs that have medicinal benefits. For example, Tsagaan Khundii spring is to cure any irregularities in digestive tract and it contains hydrocarbon, calcium, magnium, natrium, carbon dioxide and cililic acid. Mineralization is 1.5g/l. Nearby Lun spring is famous for its lung curing effects and Emt spring that is eminent for curing kidney diseases. Utaat Minchuur is the only gas-spring in Mongolia with high curative effects.

There are about 80 species of medicinal herbs, 10 species of useful plants and also the plant with various types of essence oil that is found only in Mongolia, grows in this area. Stipa, wheat-grass, filifolium, santonica, oxytropis, astragal, tare and pissabed are dominant in Dornod flora. There are total of 685 species of flora officialy reported and from it 635 species of 73 families, 50 species of 8 families of trees and bushes, and 118 medicinal, 24 extremely rare, 60 sparcing  and 560 plenteous species have been reported. The all edible floras grow in this aimag are: 10 types of stamenonion, rhubarb, wild garlic, sea-buckhorn, blackcurrant, onion, wild cherry, hawthorn, raspberry, cranberry, wild strawberry, mushrooms, hot leek, weed, red-berries, leek, wild onion, jubata, shepherds purse, dogrose and apricot. Forests here are consist of mainly larch (10.7 thous. ha), pine (22.6 thous. ha), birch (67.5 thous. ha), bush (2.2 thous. ha), aspen (1.7 thous. ha) and poplar (5.6 thous. ha).