Tongatapu is the main island of the Kingdom of Tonga and the location of its capital Nukualofa. It is located in Tonga's southern island group, to which it gives its name, and is the country's most populous island, with approximately 71,260 residents (2006), 70.5% of the national population, on 260km2. Its maximum height is 65m. Tongatapu is Tonga's centre of government and the seat of its monarchy.Tongatapu, as a commercial and transport hub, has experienced more rapid economic development than, as well as attracting many internal migrants from, the other islands of the Kingdom.GeographyThe island is 257.03km2 (or 260.48km2 including neighbouring islands) and rather flat, as it is built of coral limestone. The island is covered with thick fertile soil consisting of volcanic ash from neighboring volcanoes. At the steep coast of the south, heights reach an average of 35m gradually decreasing towards the north is a tae matausiIsland.JPG|thumb|right|250px|'Atata Island, about a 30-minute boat ride from Tongatapu.North of the island are many small isolated islands and coral reefs which extend up to 7km from Tongatapu's shores. The almost completely closed Fanga'uta and Fangakakau Lagoons are important breeding grounds for birds and fish as they live within the mangroves growing around the lagoon's shores. The lagoons were declared a Natural Reserve in 1974 by the government.The island has only but a few sandy beaches because of its raised coastlines apart from the many small islands in the north boasting some of the best beaches in Tongatapu.ClimateTongatapu has a rather cooler climate than the rest of Tonga as it is the southernmost group of islands in the country. Because of this, fruit production is lower in Tongatapu than it is in the warmer islands in the north.