Some sneak into shelters at night and then slip out in the morning, praying they won't be noticed. Others avoid government help altogether, preferring to ride out the chaos and destruction alone in a foreign land.
For illegal immigrants, the aftermath of Hurricane Katrina (search) has meant not only living without a home, money or belongings, but also steering clear of the government officials who have flocked to the area, for fear of deportation.
Tens of thousands of illegal immigrants live in the hardest-hit areas, although nobody knows exactly how many. Jeffrey Passel of the Pew Hispanic Center (search) gave a conservative estimate of 20,000 to 35,000 in Louisiana, Mississippi and Alabama.
Mexican President Vicente Fox (search) appealed to one of the largest illegal populations in the devastated region with messages in English and Spanish, urging them to seek help from Mexican consulates or U.S. rescue workers.
"We ask that you work without fear with the U.S. authorities and cooperate with them," he said. "Don't be afraid to follow rescue officials' directions. They are capable people."
But many, mindful of their long and dangerous voyage to the United States, have ignored Fox's advice, choosing to work with local churches or within tight-knit, Spanish-speaking communities.
Consular officials are struggling to reach out to their citizens, attempting to locate the missing and determine who might have died. Mexican officials have even set up "mobile consulates" for illegal immigrants living outside major cities.
So far, few are responding.
Mexican immigrant Juan Zamora, cast out of his New Orleans apartment, sought temporary shelter at a church in Denham Springs. He called his family to let them know he was fine, but was afraid to contact U.S. or Mexican officials.
"You feel destroyed because you're left with nothing and have to start all over again," said Zamora, 40, who arrived in New Orleans three years ago to work odd jobs.
Some immigrants have stayed in flooded homes and apartments to protect their belongings, knowing they will not be eligible for most federal aid.
Rumors of deportations are rife, although U.S. officials have suspended for 45 days a requirement that employers check workers' identification. Fox also said the United States has promised not to send people home in the immediate aftermath, although Washington has not confirmed that.
In some cases, the decision to stay put has been fatal.
Four roommates — three Mexicans and a Honduran — decided to ride out the storm in their trailer in Marrero. They were asphyxiated by a faulty generator after the storm passed.
Jorge Vitanza, Honduras' vice consul to New Orleans, said his staff has been scouring refugee centers and Hispanic neighborhoods to see how many of the 150,000 Hondurans living in Louisiana need help.
Of the 9,600 Salvadorans in the affected area, only 40 have gone to shelters, said Margarita de Escobar, vice minister for Salvadorans living abroad.
About 40,000 Mexicans live in Louisiana and roughly 90 have been reported missing, said Juan Bosco Marti, director-general for North America at the Mexican Foreign Relations Department.
Mexican consular officials helped 297 Mexicans displaced by the hurricane as of Tuesday, repatriating 21 to Mexico at their request.
But Marti said most Mexicans fleeing the destruction have sought shelter with extended family rather than seeking government aid.
About half of Louisiana's 30,000 Vietnamese — many of whom fled war in their homeland decades ago — have taken refuge in churches or with friends and family in Houston, which also has a large Vietnamese population.
At a Baton Rouge camp, Hector Padilla, 49, a Honduran carpenter who lived in New Orleans, said many immigrants were talking of raids by immigration authorities.
Although Padilla said he had papers, he still was nervous.
"There is always fear when you aren't a U.S. citizen," he said. "There is always fear they will get you."