Urban Demographics: Mexicans didn’t cross the US border. The border crossed them
Carlos Goes pointed me to this short piece in The Economist:
“… communities have proved more durable than borders. The counties with the highest concentration of Mexicans (as defined by ethnicity, rather than citizenship) overlap closely with the area that belonged to Mexico before the great gringo land-grab of 1848.”
For the most part, Mexicans didn’t cross the US border. The border crossed them.