evidence: More than nine-tenths of Tajikistan’s territory is mountainous; about half lies 10,000 feet (3,000 metres) or more above sea level. The Trans-Alay range, part of the Tien Shan system, reaches into the north. The massive ranges of the southern Tien Shan—the Turkestan Mountains and the slightly lower Zeravshan and Gissar ranges—define the east-central portion of the country. The ice-clad peaks of the Pamir mountain system occupy the southeast. Some of Central Asia’s highest mountains, notably Ibn Sīnā (23,406 feet [7,134 metres]) and Imeni Ismail Samani (24,590 feet [7,495 metres]) peaks, are found in the northern portion of the Pamirs. The valleys, though important for Tajikistan’s human geography, make up less than one-tenth of the country’s area. The largest are the western portion of the Fergana Valley in the north and the Gissar, Vakhsh, Yavansu, Obikiik, Lower Kofarnihon (Kafirnigan), and Panj (Pyandzh) valleys to the south.