This material is from the Federal Reserve Bank of Dallas Office of Community Affairs' publication "Texas Colonias: A Thumbnail Sketch of Conditions, Issues, Challenges and Opportunities"
Where are colonias found? Colonias can be found in Texas, New Mexico, Arizona and California, but Texas has both the largest number of colonias and the largest colonia population. Approximately 400,000 Texans live in colonias. Overall, the colonia population is predominately Hispanic; 64.4 percent of all colonia residents and 85 percent of those residents under 18 were born in the United States. There are more than 2,294 Texas colonias, located primarily along the state's 1,248 mile border with Mexico.
You need to turn the percentage around and instead of saying 64.4 percent of colonia residents were born in the United States, say 35.6 of colonia residents are Mexican immigrants, mostly illegal, and their US-born children. And to the bureaucrat who wrote "Approximately 400,000 Texans live in colonias," give your head a shake. 400,000 residents of Texas live in colonias, but they're not "Texans" or even Tejanos. They're Mexican colonists. The piece he's linking to is over six years old, and is titled Shantytowns Migrate Far North of the Border in Texas | Weak County Laws Tied to the Spread of Squalid Developments, By Sylvia Moreno, Washington Post, August 2, 2004. "Weak County Laws" means not enough building inspectors, but really it's lack of immigration enforcement that's the problem. And for the political implications see Meet The New Boss, Different From The Old Boss–Caciquismo Comes To McAllen, Texas on this blog in 2007.