Texas Teachers Salary 2010

What place does “Big Country” refer to?
A certain article that I need for work refers to a place in Texas as “Big Country”. Here is the link to the article -http://www.reporternews.com/news/2010/jan/13/areas-teacher-salaries-are-low/
I’m not from the US so I’m not that familiar with city or state nicknames.
In the article, it seems that Big Country refers to a certain region in Texas.
So does Big Country = Texas?
Everything is big in Texas.
So if something is ‘bigger than Texas’ it’s massive in size.
Texans have the biggest amount of Billionaires on the planet.
Texans have big hats and until recently big caddilacs.
