For 45 years it was a part of British India and returned to Nepal in 1860 in recognition for supporting the suppression of the Indian Independence movement in 1857.

In 1982, it was proclaimed as the Royal Bardia Wildlife Reserve and extended to include the Babai River Valley in 1984.

Since farming has ceased in the Babai Valley, the naturally regenerated vegetation makes the area a prime habitat for wildlife.

[5] The wide range of vegetation types in forests and grasslands provides excellent habitat for 642 faunal species.

The Karnali-Babai river system, its small tributaries, and myriad oxbow lakes are habitats for 125 recorded species of fish.

[11] In May 2006, a reconnaissance survey was carried out in the Babai River floodplain, which revealed an alarming decline in the rhino population.

[14] In 1985, two large elephant bulls were spotted for the first time in the park, and named Raja Gaj and Kanchha.

[16] Current checklists include 407 bird species, among them the Bengal florican, white-rumped vulture, peafowl, and bar-headed geese, which are symbolic of the park.

[5] Lesser florican and sarus crane are present; grey-crowned prinia, jungle prinia, pale-footed bush warbler, aberrant bush warbler, striated grassbird, golden-headed cisticola and chestnut-capped babbler occur in the park's grasslands.