transnational suburb
n. A suburb made up mostly of immigrants who maintain strong ties to their home countries.
Many Mexican immigrants keep homes in both countries. Some even vote in Mexican elections while living in the United States.

The results of such migratory trends are transforming U.S. cities.

Social scientist Mike Davis has coined the phrase "transnational suburbs" to describe an emerging phenomenon. Natives of particular Mexican villages are moving en masse into the same U.S. neighborhoods, creating de facto satellites of their hometowns.
—Jack Chang, “Unrecognized live, give life and die in our midst,” Contra Costa Times, July 17, 2002
2000 (earliest)
[The] ease of telecommunications and air travel has changed the nature of immigration, allowing Latinos, especially those from Indian communities, to easily maintain their culture, drawing strength from it in ways early European immigrants couldn't.

These "transnational suburbs" have fostered remarkable progress among some Latinos. The tight U.S. enclaves of Zapotecs from the Mexican state of Oaxaca, for example, have been known to save up money and then as a group buy apartment buildings from slumlords. At the same time, their kids attend college at "a rate that defies the poverty and illiteracy of their parents."
—Oscar C. Villalon, “How Spanish-speaking peoples are transforming our country,” The San Francisco Chronicle, September 24, 2000