The Muthurajawela marsh is situated towards the south of Negombo and is the largest brackish coastal bog in Sri Lanka. The wetland was declared as a sanctuary due to its diverse flora and fauna by the government of Sri Lanka in 1996 and is a popular tourist destination in Negombo owing to the sights and sounds it has to offer.
The marsh is connected to the Negombo lagoon and the Dutch canal system and most of the swamp is accessible only by boat but there are many tour operators willing to offer services ranging from Rs. 2000/- and up per person and will offer a tour by boat around the swamp with an experienced guide/spotter.
The swamp has over 200 species of plants including many varieties of mangroves. Migratory birds can be usually seen between the months of September and April and there are close to 80 species of endemic birds including kingfishers, purple herons and brahminy kites.
As for the fauna there are many species of vertebrates such as crocodiles, water monitors and monkeys and invertebrates, notably, dragonflies and butterflies.
It is truly an urban sanctuary worth visiting if in the Negombo area.