Palestine is located on the east side of the Mediterranean Sea. It constitutes the southwestern part of a large geographical unity in the east northern part of the Arab world, called Bilad El-Sham, The Levant. In addition to Palestine, Sham includes Lebanon, Syria and Jordan. They constitute the Fertile Crescent along with Iraq.
In the ancient times, Palestine represented one of the most important trade routes. It connected the homes of civilizations of the Nile Valley and the southern areas of the Arab peninsula on one hand and the homes of civilizations in the northern areas in Belad El-Sham and Iraq on the other. Palestine has always been a passage for trade caravans before and after the coming of Islam.
The importance of the commercial location of Palestine increased during the Mamluks era when it used to be a passage for the commercial caravans that carried goods from the Far East to Europe and vice versa. The trade ships used to stop at Aden and unload their cargo so that it would be transported by caravans across Yemen and Hejaz and then to the Palestinian ports on the Mediterranean Sea. The ships in the ports waited to be loaded with different kinds of goods such as silk, perfumes, jewelry, and the like, to be transferred to European ports. The West Bank covers 5,655 km2 and is 130km long and ranges between 40 and 65 km in width. The land area of the Gaza Strip is equal to 365 km2 and is 40 km long and 5-12 km wide, the West Bank and Gaza Strip can be characterized by its geography, biodiversity and its multi-climate that varies between coastal, desert, mountains and valleys.
There are five main relief and climate regions in Palestine: First, the Jordan valley from the western bank of the river to the north of the Dead Sea. Second, the Eastern hills from the eastern part of the west bank, to the east of Jenin. Third, Central Highlands--the largest part of the west bank from Jenin to Hebron. Forth, Gaza Strip which lies along the coast of the Mediterranean in the western part of the territory. And Fifth, the Fertile Plains Region, Marj Bin Amer (Bin Amer Meadow), covering the area from Jenin to Tulkarem.
Here’s some websites which explain more about the location and area in Palestine:
Political geography: http://www.justjerusalem.org/political-geography
Desk Study on the environment in the occupied Palestine territories: http://www.unep.org/download_file.multilingual.asp?FileID=105
Recommended Books about geography in Palestine: http://www.sup.org/books/title/?id=17079