Agusan del Sur is a landlocked province of the Philippines located in the Caraga region in Mindanao. Its capital is Prosperidad and borders, from the north clockwise, Agusan del Norte, Surigao del Sur, Davao Oriental, Compostela Valley, Davao del Norte, Bukidnon, and Misamis Oriental.EtymologyAgusan derived its name from the local dialect, agasan, meaning "where the water flows", referring to the Agusan River that splits the land and meanders south to north in a 250km rush to Butuan Bay. It is third largest river in the country and served as highway for the Spanish colonizers in gaining access to inner northeastern Mindanao.HistoryThe Agusan Valley was settled by a variety of cultural communities like the Manobos, Mamanwas and Higaonons. Archeological excavations in the lower Agusan valley plains have uncovered evidence of strong relationships between the region and the Southeast Asian states. A golden image of Javan-Indian design unearthed in the 1920s and molten jars uncovered in Prosperidad are indications that the region had commercial and cultural ties with the coast.