The Agusan Marsh Wildlife Sanctuary is a protected area in Agusan del Sur, Philippines declared by President Fidel V. Ramos. The marshland acts like a sponge, as it is nestled in the midwaters of the Agusan River drainage basin. Within its lakes, several floating communities can be found. The sanctuary was home to the 20.24 feet saltwater crocodile Lolong, the world's largest captive crocodile.
It is located in the municipalities of Bunawan, La Paz, Loreto, Rosario, San Francisco, Talacogon, and Veruela in the province of Agusan del Sur. The marsh was declared as a Ramsar Wetland Site in 1999. The site is currently being re-evaluated for nomination to the tentative list of UNESCO.