Mongolia is a huge, landlocked country: 1,566,000 sq km in area - about three times the size of France, and over twice the size of Texas. Apart from the period of Mongol conquest under Chinggis Khaan and Kublai Khaan, Mongolia was, until the 20th century, about twice its present size. A large chunk of Siberia was once part of Mongolia, but is now securely controlled by Russia, and Inner Mongolia is now firmly part of China.
Conservationists divide Mongolia into six zones:
Desert. Spread out over the most southern sliver of the Gobi Desert and stretching into China, this zone has very little vegetation, livestock, wildlife, population or rain.
Desert Steppe. This includes the lower-lying areas of western Mongolia and most of the Gobi (except for the far southern section). Covering about 20% of the country, this dry and sparsely populated zone has salt lakes and sand dunes.
Mountain. This zone covers the Khangai and Mongol Altai mountains in Arkhangai, Khovd and Bayan-Olgii provinces. It is very cold and wet all year and sparsely populated, but home to some of the country's most endangered animals.
Mountain Forest Steppe. These grasslands are found in the central and northern provinces (dominated by the Orkhon and Selenge rivers), and in the western provinces of Khovd and Bayan-Olgii. The zone covers about 25% of Mongolia, is home to gazelles and antelopes, and has a relatively high number of people and livestock.
Steppe. This is spread over the southern part of Tov province and most of eastern Mongolia. Covering about 20% of the country, it is home to vast numbers of gazelles, birdlife and livestock, but is sparsely populated.
Taiga. This area of larch and pine forests is found in Khentii province, around Khovsgol Nuur lake, and stretches into Siberia. It is also wet and cold.
The southern third of Mongolia is dominated by the Gobi Desert. Although barren-looking, it has sufficient grass to support scattered herds of sheep, goats and camels. Most of the Gobi is not sandy, nor full of sand dunes. Much of the rest of Mongolia is covered by grassland, home to Mongolia's famed horses which Chinggis Khaan Used so successfully in his wars of conquest.
Mongolia is also one of the highest countries in the world, with an average elevation of 1580m. In the far west are Mongolia's highest mountains, the Mongol Altai Nuruu, which are permanently snowcapped. The highest peak, Tavanbogd Uul (4374m), has a magnificent glacier towering over Mongolia, Russia and China. Between the peaks are stark deserts where rain almost never falls. It's an incredibly beautiful, rocky landscape with a few scattered forests in some of the better-watered valleys.
Near the center of Mongolia is the Khangai Nuruu range, with its highest peak (Otgon Tenger Uul) reaching 3905m. On the north slope of these mountains is the source of the Selenge Gol, Mongolia's largest river, which flows northward into Lake Baikal in Siberia. While the Selenge Gol is the largest in terms of water volume, the longest river is the Kherlen Gol in eastern Mongolia.
Just to the north-east of Ulaanbaatar is the Khentii Nuruu, the highest mountain range in eastern Mongolia and by far the most accessible to hikers. It's a heavily forested region with raging rivers and impressive peaks, the highest being Asralt Khairkhan Uul (2800m).
Mongolia has numerous saltwater and freshwater lakes which are great for camping, watching birdlife, hiking, swimming and fishing. The most popular is the magnificent Khovsgol Nuur, which contains up to 2% of the world's fresh water. The largest is the low-lying, saltwater Uvs Nuur. Also worth exploring are Achit, Uureg, Khar Us and Terkhiin Tsagaan lakes.
Other geological and geographical features include underwater and above-ground caves, some with ancient rock paintings; dormant volcanoes; hot and cold mineral springs; the Great Lakes depression in western Mongolia and the Darkhadyn Khotgor depression west of Khovsgol Nuur; and the Orkhon Khurkhree waterfalls.
Mongolia is divided into 18 provinces (aimag) - plus four independent municipalities, which are also sometimes called aimags. These are Ulaanbaatar, Darkhan-Uul (which contains Darkhan city), Orkhon (with Erdenet city) and Gov-Sumber (with the Free Trade Zone town of Choir). The aimags are further divided into a total of 298 districts (sum).

Mongolia is a land of extremes. It is so far inland that no sea moderates the climate. Only in summer does cloud cover shield the sky. Humidity is zilch, and sunshine is intense. With over 260 sunny days a year, Mongolia is justifiably known as the 'Land of Blue Sky'.
Long subarctic winters are the norm, however, and you can see snow in the Gobi Desert as late as April, and some lakes remain frozen until June. There is a short rainy season from Mid-July to September, but the showers tend to be brief and gentle. Because of the high altitude, evenings are cool even in summer. Mongolia is a windy place, especially in spring.
When the wind blows from the north, temperatures drop sharply, but when the wind drops, the weather warms up just as rapidly. One day you're walking around in a T-shirt and sandals, the next day you need an overcoat and boots, then the following day it's back to T-shirts. This is especially the case during the brief autumn and spring.
In the Gobi, summer temperatures hit 40 degrees Celsius, but winter winds often send the mercury plummeting to minus 30 or lower. Even in summer, the evenings can be astoundingly cold. The steppe is always chilly - the July average is only 10 degrees Celsius, and even spring and autumn are frosty. Winter is no joke - minus 50 degrees Celsius is not unknown. Mountainous areas are always cold and windy; many peaks are permanently snow-capped. Low-lying areas, such as Uvs Nuur lake in the west, also suffer from extreme temperatures.
In Ulaanbaatar, the winter (October to April) is long and cold - with temperatures often dropping down to minus 30 degrees Celsius in January and February. You can expect some horrific dust storms during the short spring (May to June). The summer (July to September) is pleasant without being hot. It can still suddenly turn cold and, unfortunately, most of the city's rain falls in this period.

Greenway, Paul, Storey, Robert & Lafitte, Gabriel, Lonely Planet - Mongolia, Second Edition, Lonely Planet Publications, Hawthorn, Australia, 1997, pp. 19-21.