Bardiya National Park covers 968 km2 (374 sq mi) occupies most of the northern half of the district.

It provides forest, grassland and riverine habitat for endangered mammal, bird and reptile species.

The Karnali, one of Nepal's largest rivers, divided into multiple branches when it reaches the Terai.

[5] 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.

[8] Ethnicity/caste: 53.3% were Tharu, 11.3% Chhetri, 8.7% Hill Brahmin, 5.7% Kami, 2.9% Magar, 2.6% Muslims, 2.3% Thakuri, 1.9% Yadav, 1.8% Damai/Dholi, 1.1% Mallaha, 0.9% Lodh, 0.8% Chamar/Harijan/Ram, 0.7% Gurung, 0.7% Sanyasi/Dasnami, 0.6% Newar, 0.6% Sarki, 0.3% Dusadh/Pasawan/Pasi, 0.3% Kurmi, 0.3% Tamang, 0.3% other Terai, 0.2% Badi, 0.2% Terai Brahmin, 0.2% other Dalit, 0.2% Dhobi, 0.2% Hajam/Thakur, 0.2% Halwai, 0.2% Kathabaniyan, 0.2% Lohar, 0.2% Raji, 0.1% Bengali, 0.1% Gaine, 0.1% Kayastha, 0.1% Koiri/Kushwaha, 0.1% Kumal, 0.1% Rajbanshi, 0.1% Teli and 0.1% others.