There are 8 billion people on Earth.

So if you gave each family of four a 50x100 foot plot of land (i.e., 5,000 square feet of space), then you could fit eight such plots per acre (with 3,500 square feet to spare for communal space) -- because an acre has 43,560 square feet.

So you would be able to fit 32 people per acre, and since Texas has 171 million acres, you would be able to fit 5.4 billion people in Texas. Since the world has more than 5.4 billion people, we will have to conquer Mexico or Oklahoma.

Long story short, there will be plenty of space left over in Asia.