Arunchal Pradesh, one of the most sparsely populated states of India, borders China, Bhutan and Myanmar. There are five major rivers – Kameng, Subansiri, Siang (later the Brahmaputra in Assam), Lohit and Tirap and the mountation ranges follow the river systems. Arunachal Pradesh, 'the land of the dawn lit mountains', is one of the most pristine areas in India. Home to a complex mix of communities, its people are friendly, colourful and simple. The history of Arunachal Pradesh is a virtual treasure trove of myths and fascinating traditions, but the recorded history of this state is available only from the 16th century onwards, when the Ahom kings began to rule Assam. Since 1947, it was a part of the North East Frontier Agency and was later made a Union Territory. Arunachal Pradesh was made a full fledged state on 20th February, 1987.It is a land of lush green forests, deep river valleys and beautiful plateaus. The land is mostly mountainous with the Himalayan range along the northern borders criss-crossed with ranges running north-south. These divide the state into five river valleys: the Kameng, the Subansiri, the Siang, the Lohit and the Tirap. All these are fed by snow from the Himalayas and countless rivers and rivulets.
There are 26 major tribes and a number of sub-tribes inhabiting the area. Most of these communities are ethnically similar, having derived from original Mongoloid stock but their geographical isolation from each other has brought amongst them certain distinctive characteristics in language, dress and customs. Broadly, the entire population may be divided into three cultural groups based on their socio-politico-religious affinities. The Monpas and Sherdak Pens of Tawang and West Kameng districts follow the lamaistic tradition of Mahayana Buddhism. Culturally similar to them are Membas and Khembas who live in the high mountains along the northern borders, Khamptis and Singphos inhabiting the eastern part of the State are Buddhists of Hinayana sect. They are said to have migrated from Thailand and Burma long ago and still using ancient scripts derived from their original homeland.