I would say that the vast majority of Texas is sparsely populated. The bulk of our population comes from Dallas/Fort Worthless, Houston, Austin, San Antonio, and a handful of other large and medium sized cities. Many counties have very few people due to desert conditions or because they are hundreds of miles from anything else. The western half of Texas is a totally different place than the eastern half. Just take a look at one of those dark sky websites that shows lights on earth at night. Pretty dark to the west of IH 35! That is true for most of the western states too. Draw a line from Brownsville up through Fort Worthless and on up through St. Paul, MN and most of the lights are to the east of that line and most of the area to the west is dark until you get to CA, OR, and WA state.