Actually Texas has very little public land.
Here's a cut out of an article from the Texas Land Conservatory:
Why is land conservation important in Texas?
Texas loses over 200,000 acres of open land every year to the pressures of development and urban sprawl.
Ninety-five percent of Texas’ land is privately-owned, which is vasty different from other western states of our scale, natural beauty and environmental diversity. Because of this, private lands conservation is one of the only comprehensive methods for protecting lands in Texas.
The population of Texas will grow 71% in the next 30 years, with pressure most heavily on land in counties surrounding our urban areas.
From 1997 to 2007, the top 50 high-growth counties accounted for 93% of the state’s population growth, while experiencing 50% of the decline in agricultural lands.*
Overall, Texas experiences a loss of about 270 acres of agricultural land for each 1,000 new residents added to the population.*
That's 95% of Texas that's off limits unless you know someone or pay a trespass fee...kinda sucks since there is so much land there.