The First Geography Congress, which was convened in Ankara in 1941, at the conclusion of the research that had continued for a long time, separated Turkey into seven geographical regions. During the congress activities, the fact that Turkey is surrounded by sea on three sides, the presence of mountain ranges lying parallel to the length of the long coastline, the fact that these mountains separate the high, but slightly steep and uneven central section from the influence of the sea and because of this, factors such as the climate, natural plant cover and the distribution of types of agriculture, and the influences of these on the transportation systems and the types of housing between the coastal strip and the central sections, had been taken into consideration and it was possible to divide Turkey into four border and three inner regions. The first four of the seven regions determined were given the names of the seas which are adjacent to them (the Black Sea, the Marmara, the Aegean and the Mediterranean Regions). The other three regions were named in accordance with their location in the whole of Anatolia (Central, Eastern and Southeastern Anatolia Regions).
The Marmara region covers the area encircling the Sea of Marmara, includes the entire European part of Turkey, as well as the northwest of the Anatolian plain. Whilst the region is the smallest of the regions of Turkey after the Southeast Anatolia region, it has the highest population density of all the regions.
The most important peak in the region is Uludag (2,543 metres), at the same time it is a major winter sports and tourist centre. In the Anatolian part of the region there are fertile plains running from east to west.
The Aegean region extends from the Aegean coast to the inner parts of western Anatolia. There are significant differences between the coastal areas and those inland, in terms of both geographical features and economic and social aspects.
In general, the mountains in the region fall perpendicularly into the sea. and the plains run from east to west. The plains through which Gediz, Kücük Menderes and Bakircay rivers flow carry the same names as these rivers.
The Central Anatolian region is exactly in the middle of Turkey and gives the appearance of being less mountainous compared with the other regions. The main peaks of the region are Karadag, Karacadag, Hasandag and Erciyes (3.917 metres).
The Eastern Anatolia region is Turkey's largest and highest region. About three fourths of it is at an altitude of 1,500-2,000 metres. Eastern Anatolia is composed of individual mountains as well as of whole mountain ranges, with vast plateaus and plains. The mountains: There are numerous inactive volcanoes in the region, including Nemrut, Suphan, Tendurek and Turkey's highest peak, Mount Agri (Ararat), which is 5,165 metres high.
At the same time, several plains extended along the course of the River Murat, a tributary of the Firat (Euphrates). These are the plains of Malazgirt, Mus, Capakcur, Uluova and Malatya.
The Southeast Anatolia region is notable for the uniformity of its landscape, although the eastern part of the region is comparatively more uneven than its western areas.