First established in 1908 as a reserved forest, it subsequently was designated a game (1916) and wildlife (1950) sanctuary before becoming a national park in 1974. Kaziranga was designated a UNESCO World Heritage site in 1985. The park has an area of some 165 square miles (430 square km) and lies between the Brahmaputra River and the Karbi (Mikir) Hills. Much of the park is marshland interspersed with large pools fringed with reeds, patches of elephant grass, scattered trees, and thickets. Wildlife includes the world's largest population of great Indian one-horned rhinoceroses (Rhinoceros unicornis), tigers, leopards, panthers, bears, elephants, wild pigs, hog deer, swamp deer, buffalo, and pelicans, storks, and other waterfowl. Seasonal flooding regularly inundates much of the park and kills numerous animals; the land near the river is also subject to erosion. These events have been major factors for a gradual decrease in animal populations over the years.

Guest houses perched above the main road at Kohra, near the southern boundary, give a panoramic view of the Himalayas on the rare occasions when the sky is clear. There are several low watchtowers, and elephant rides are available for viewing wildlife in the swampland.