Hara-Huna was an ancient Chinese kingdom and inhabited by the Hara Hunas tribe close to the Himalayas who had limited interaction with the Indian kingdoms, thus they were identified in the epic Mahabharata.
They lived in the Xinjiang province of China, east of Kashmir. However they were nomadic people who changed their settlements time to time.
The Pandava hero Nakula, visited this place during his western military campaign for collecting tribute for Yudhishthira's Rajasuya sacrifice. This could be a branch of Hara-Hunas migrated to the west of Ancient India.
Nakula, after defeating the mighty Gramaniya that dwelt on the shore of the sea, and the Sudras and the Abhiras that dwelt on the banks of the Sarasvati River, and all those tribes that lived upon fisheries, and those also that dwelt on the mountains, and the whole of the country called after the five rivers (Punjab), and the mountains called Amara, and the country called Uttarayotisha and the city of Divyakutta and the tribe called Dwarapala, by sheer force, reduced to subjection the Ramathas, the Harahunas, and various kings of the west. (2,31)
Numberless Chinas and Sakas and Uddras and many barbarous tribes living in the woods, and many Vrishnis and Harahunas, and dusky tribes of the Himavat, and many Nipas and people residing in regions on the sea-coast came to the Rajasuya sacrifice performed by Pandava king Yudhishthira. (2,50)