Northeastern Indian state of Mizoram has Aizawl as its capital and seat of government. The word "Mizo," which is how the native residents refer to themselves, and the word "Ram," which in Mizo means "land," are combined to form the name of the state. "Mizo-ram" hence refers to the "country of the Mizos." It is the southernmost landlocked state in the northeastern part of India, bordering Tripura, Assam, and Manipur, three of the Seven Sister States. The state also borders Bangladesh and Myanmar on either side of a 722-kilometer (449-mile) border. Mizoram, along with a number of other northeastern Indian states, was formerly a part of Assam until it was separated as a Union Territory in 1972. The State of Mizoram was formally established as India's 23rd state on February 20, 1987, thanks to the adoption of the 53rd amendment to the Indian Constitution by the Indian Parliament in 1986. A census taken in 2011 indicated that Mizoram had 1,091,014 residents. The state has the second-lowest population in the nation. Mizoram has a total area of 21,087 square kilometers, of which 91% is covered in forest. About 95% of people in Mizoram are descended from several tribes. Mizos first arrived in the region in the 16th century, migrating in waves from Southeast Asia. Through the eighteenth century, this immigration continued. Mizoram has the highest percentage of tribal people of any state in India. As a Scheduled Tribe, the Mizoram people are currently protected under the Indian constitution. One of three Indian states, Mizoram has an overwhelming Christian population (87%). Most of its residents are Presbyterians in the north and Baptists in the south, but they are members of a variety of Christian groups.