<Tr> <Th> Longest river </Th> <Td> Karun </Td> </Tr> <Tr> <Th> Largest lake </Th> <Td> Lake Urmia </Td> </Tr> <P> Geographically, Iran is located in West Asia and borders the Caspian Sea, Persian Gulf, and Gulf of Oman . Its mountains have helped to shape both the political and the economic history of the country for several centuries . The mountains enclose several broad basins, on which major agricultural and urban settlements are located . Until the 20th century, when major highways and railroads were constructed through the mountains to connect the population centers, these basins tended to be relatively isolated from one another . </P> <P> Typically, one major town dominated each basin, and there were complex economic relationships between the town and the hundreds of villages that surrounded it . In the higher elevations of the mountains rimming the basins, tribally organized groups practiced transhumance, moving with their herds of sheep and goats between traditionally established summer and winter pastures . There are no major river systems in the country, and historically transportation was by means of caravans that followed routes traversing gaps and passes in the mountains . The mountains also impeded easy access to the Persian Gulf and the Caspian Sea . </P>

This asian country borders the caspian sea and persian gulf