Tierra del Fuego is an archipelago located approximately between southern latitudes 52° and 56º, framed by western meridians 63º and 75º. Its total area is 1,268,271 km2.
A multitude of large, medium and small islands and isle, huddle around a land greater or main island, whose shape can be simplified as an almost equilateral triangle, which has a base of two hundred and fifty miles facing south, and it extends from the passage of Brecknock to the Strait of Le Maire. Its triangular height can be measured from Cape St. Pio to the parallel of Punta Anegada, amounting to about 150 miles.
The Bigger Island of Tierra del Fuego has different characteristics in its climate, landform and vegetation that can divide into three ecological zones: Magellan steppe, ecotone and mountain ranges.
The Magellan steppe covers the entire northern part of the island, being its southern boundary a line running from west to east from the international border with Chile over Grande river, to Punta Maria on the Atlantic coast. It covers an area of 418,000 hectares. This area has a temperate climate, cold, semi-arid. The average annual temperature is 5° C and the mean coldest month (June) is 0° C and the warmest month (January) is 9° C. Rainfall is fairly evenly distributed throughout the year, although with a decrease in the August-October period, totaling 380 mm. Prevailing winds are from the west, northwest and southwest areas, blowing with greater intensity (strong to very strong) in the spring and summer. Snowfall in this area are generally rare and occur when the soil remains covered briefly. The floor and most of the streams remain frozen on the surface during the period May to August. Like all the island, this area does not have frost-free period.
The steppe is the area that has better aptitude for livestock production and was the first to be occupied by the end of the 19th century and the beginning of the 20th by the early pioneers.
The ecotone comprises the central part of the island. It is bordered to the north with the Magellan steppe and to the south and southwest to the mountain area, being the boundary between a line from the point of 54° south latitude to the western shore of Lake Yehuin, and from the eastern end of it to Cape Irigoyen, over the Atlantic. It covers an area of 466,000 hectares.
It is characterized by the presence of trees, forming small patches of open woodland in the north. The woodland increases in density and height to the south and west, joining the community of beech trees.
The relief appears more rugged than in the steppe, covered by high mountains and forming plains in the low usually traversed by a stream.
Climate is more humid than in the steppe, increasing rainfall from north to south. The snowfalls are more frequent and intense, remaining a large part of the area covered by snow throughout the winter. The floor and most of the streams remain frozen on the surface during this period.
The mountain area covers the entire south of the island and its name is due to much of the same is crossed by the Andes range. It covers an area of 1,242,000 hectares. The landscape is presented in the form of mountain ranges, which does not exceed a maximum height of 1,500 m above sea level. The valleys that limit the mountain ranges form bog and meadows of large size, usually crossed by streams. Here are the major lakes of the Island: lakes Yehuin, Chepelmesh, Escondido and Fagnano or Kami.
The Beagle Channel coast occurs abruptly interrupted by narrow strips of land, with gently sloping towards the channel, covered by herbaceous vegetation and snow mainly on high ground. Ushuaia data give an annual rainfall of 540 mm. And an average temperature of 5° C. The average temperature in the coldest month (July) is 0° C and in the warmest month (January) is 9° C. Summer is temperate-cold and wet. It should be noted that due to the influence of the sea, the Atlantic coast and the Beagle Channel it have milder weather than the rest of the area.