Bardiya was part of Nepal before it was ceded to the British East India Company in Sugauli Treaty. Later during the administration of Jang Bahadur Rana it was returned to Nepal along with Banke, Kailali and Kanchanpur. In the early twentieth century, Bardiya was still covered with forest and sparsely populated with indigenous tribal people called Tharu. Additional Tharus immigrated west from Dang and Deukhuri Valleys after they were displaced by Nepalis from the hills. Later these hill people also migrated into Bardiya, however Tharu from Dang and Deukhuri still make up a majority of Bardiyas population. Other tribals called Sonaha live near the Karnali River and western periphery of Bardia National Park, who are historially engaged in extracting golden ores from sediments of river and fishing.