Rio Grande Valley. It's the name for the region that is the southern tip of Texas. It's overwhelmingly Latino, and was never economically integrated into the rest of Texas as Tejanos (the Mexican settlers in Texas) were able to retain power there after 1834. RGV is basically split between Tejanos (who have US citizenship) and immigrants (documented and undocumented) from neighboring Mexico. Within the RGV, a handful of Tejano political families essentially run everything there. There have been some attempts to clean up politics and governance there, but it's hard when a significant portion of the population there cannot vote, and a significant portion of the rest will vote for existing patronage networks. It's the similar issue in the Missippi Delta, portions of Central California, and portions of Upstwre New York - multi-generational patronage networks have a stranglehold on power.