The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur to the east; Meghalaya, Tripura, Mizoram and Bangladesh to the south; and West Bengal to the west via the Siliguri Corridor, a 22 kilometres (14 mi) strip of land that connects the state to the rest of India.
Assam is known for Assam tea and Assam silk. The state was the first site for oil drilling in Asia. Assam is home to the one-horned Indian rhinoceros, along with the wild water buffalo, pygmy hog, tiger and various species of Asiatic birds, and provides one of the last wild habitats for the Asian elephant. The Assamese economy is aided by wildlife tourism to Kaziranga National Park and Manas National Park, which are World Heritage Sites. Sal tree forests are found in the state which, as a result of abundant rainfall, look green all year round. Assam receives more rainfall than most parts of India; this rain feeds the Brahmaputra River, whose tributaries and oxbow lakes provide the region with a hydro-geomorphic environment.
The precise etymology of the modern anglicised word “Assam” is ambiguous. In the classical period and up to the 12th century the region east of the Karatoya river, largely congruent to present-day Assam, was called Kamarupa, and alternatively, Pragjyotisha. In medieval times the Mughals used Asham (eastern Assam) and Kamrup (western Assam), and during the British colonial era, the British used Assam.
According to a late text, Kalika Purana (c. 9th–10th century AD), the earliest ruler of Assam was Mahiranga Danav of the Danava dynasty, which was removed by Naraka who established the Naraka dynasty. The last of these rulers, also Naraka, was slain by Krishna. Naraka’s son Bhagadatta became the king, who (it is mentioned in the Mahabharata) fought for the Kauravas in the battle of Kurukshetra with an army of kiratas, chinas and dwellers of the eastern coast.