Larger even than Texas, actually. TX is 262,000 sq miles.
But much smaller than Alaska, which is 572,000 sq miles.
For my own reference, I was looking at the "Four Corners" states: Colorado, Utah, New Mexico, and Arizona when I was working out my topography. I neglected to go back there before I did my settlements. Even so, considering the number of ruined cities I placed in Tawaren, I think my pre-plague population level would be about right, and a map of this scale wouldn't necessarily show smaller populations unless they were significant in some other way.