4.1 The country\n\n It has a total area of 523115 km² and a coastline of 2600 km. Four south-flowing rivers, Chao Phraya, Mae Klong, Bang Pa Kong and Chin, drain nearly two-thirds of the country. The Mekong river and its western tributaries, mainly the Pak river, drain the northeast.

Chao Phraya River, principal river of Thailand. It flows south through the nation's fertile central plain for more than 225 miles (365 km) to the Gulf of Thailand.