The Mahaweli River (Sinhalese: මහවැලි ගඟ, literally "Great Sandy River"; Tamil: மகாவலி ஆறு [mahawali gangai]), is a 335 km (208 mi) long river, ranking as the longest river in Sri Lanka. Its drainage basin is the largest in the country, and covers almost one-fifth of the total area of the island. The river reaches the Bay of Bengal on the southwestern side of Trincomalee Bay.