New South Wales is set to get a new national park - twice the size of ACT - which is home to 27 threatened species.
The 153,415 hectare Narriearra Station in far north west NSW, just east of Tibooburra, is the largest purchase of private land for national parks in the state's history.
The northern boundary follows the NSW/Qld state border along the dog proof fence. It is to the east of Sturt National Park.
Environment minister Matt Kean said the purchase will help protect threatened species, important habitat and wetlands.
Narriearra, which had been owned by the O'Connor family, is also linked to the ill-fated Burke and Wills expedition, with two expedition campsites on the property.
"Narriearra Station stretches across the outback Channel Country and includes part of the Bulloo River floodplain, ephemeral wetlands and landscapes currently not found anywhere in NSW national parks," Mr Kean said.
He said Narriearra is an important refuge for threatened wildlife, with more than 25 threatened animal species, including nearly 90 per cent of NSW's critical habitat and breeding areas for the nationally endangered grey grasswren. Other threatened species include the grey falcon, redthroat and Australian bustard.
The aquisition secures a key section of a nationally important wetland - the Caryapundy Swamp - which can host tens of thousands of waterbirds including pelicans, straw-necked ibis, egrets and whiskered terns during inland flood events.
"Narriearra along with the nearby Sturt National Park, will create a vast near-contiguous conservation area of almost half a million hectares, or twice the size of the ACT.
"Adjoining the Pindera Downs Aboriginal Area, Narriearra contains many significant and valuable stone artefacts, tools and stone arrangements."
The park doesn't have a name yet. Tibooburra Local Aboriginal Land Council to suggest a name for the new national park.