The history of Anini and the surrounding Dibang Valley is primarily the history of the Idu Mishmi tribe, who have inhabited these rugged mountains for centuries. Oral traditions map a complex lineage and migration routes across the Himalayan terrain, long before modern international borders were drawn. For generations, the region remained largely unadministered by outside forces, including the British Empire, which established a loose "Inner Line" to demarcate the foothills from the tribal highlands.
Following India's independence in 1947, the region was integrated into the North-East Frontier Agency (NEFA). The Sino-Indian War of 1962 brought intense strategic focus to Arunachal Pradesh, prompting the Indian government to slowly initiate infrastructure and administrative integration in these border areas.
Anini's modern civic history formally began in June 1980, when the vast Lohit District was bifurcated to create the Dibang Valley district, with Anini selected as its headquarters. In 2001, the district was further divided into the Upper and Lower Dibang Valleys (with Anini remaining the headquarters of the upper portion). Over the last few decades, Anini has transitioned from a completely isolated tribal settlement into a vital administrative and security node, seeing gradual improvements in road connectivity and modern amenities.