The Texas Hill Country is roughly 11 million acres. Chile has recently announced 5 new national parks totaling 10 million acres. 
Chile has created five sprawling national parks to preserve vast tracts of Patagonia – the culmination of more than two decades of land acquisition by the US philanthropists Doug Tompkins and Kristine McDivitt Tompkins and the largest donation of private land to government in South America.
The five parks, spanning 10.3m acres, were signed into law on Monday by Chile’s president Michelle Bachelet, launching a new 17-park route that stretches down the southern spine of Chile to Cape Horn… Read more from The Guardian