The statement that best describes the population of Texas at the time of Mexican independence in 1821 is:
"Texas was a sparsely populated region that included only three major Tejano settlements."
At the time of independence, Texas had a relatively low population density, with the Tejano population primarily concentrated in specific areas. While there were some Anglo settlers beginning to arrive, the overall population was still predominantly Tejano, and the region was not highly populated compared to later periods.