The milky stork's range is restricted to Southeast Asia, where it is widely but patchily distributed. It occurs in Sumatra (its global stronghold), Java, Sulawesi, eastern Malaysia, Cambodia, southern Vietnam (where it probably largely recolonised after the war of 1963–75), Bali, Sumbawa, Lombok and Buton. It historically occurred in southern Thailand, but is now very likely extinct here. One perfect adult male milky stork specimen from Setul in Peninsula Thailand taken from 1935 was later found among collections of the Zoological Reference Collection at the National University of Singapore, suggesting that the species was formerly resident here. The discovered specimen was the first, and probably also the last milky stork to be reported from Thailand, although this stork probably still occasionally visits Thailand as a vagrant. It is also vagrant elsewhere to countries such as Bali and Sumbawa, and is resident on Sumatra, Java and Sulawesi (all within Indonesia). The milky stork was first reported on Sulawesi when a group of five apparently resident individuals was sighted there in 1977. The island of Madura may also support an important population after 170 individuals were sighted there in 1996.