The Ayeyarwady River (Burmese: ; formerly known as the Irrawaddy River) flows through the centre of Myanmar (formerly Burma). It is Myanmar's most important commercial waterway. Its total drainage area is about 158,700 square miles (411,000 square km). It is about 1,350 miles (2,170 km) long. The Ayeyarwaddy River starts in Kachin State, at the confluence of the Mali Hka and N'Mai Hka rivers. The western Mali Hka branch arises from the end of the southern Himalayas, north of Putao, and (like the main river) is called Nam Kiu in the Shan language. The Ayeyarwaddy River dissects the country from north to south and empties through a nine armed delta into the Indian Ocean. In colonial times, before railways and automobiles, the river was known as the "Road to Mandalay". Although navigable by large vessels to Myitkyina for a distance over 1600 km from the ocean, the river is also full of sandbanks and islands, making such navigation difficult. For many years, the only bridge built to cross the Ayeyarwady River was the Inwa Bridge. The name "Ayeyarwady" is believed to have derived from the Sanskrit term "airavati", meaning "elephant river". The Irrawaddy gives its name to a dolphin, the Irrawaddy Dolphin (Orcaella brevistosus), which is found in the river. Though sometimes called the Irrawaddy River Dolphin, it is not a true river dolphin, since it is also found at sea.