In New York, 23-year-old Zuleima Dominguez and other members of her Mexican family are careful about answering the door, and get worried and start making phone calls when someone doesn't come home on time.
In Philadelphia, immigrants are carrying around wallet-size "Know Your Rights" guides in Spanish and English that explain what to do if they're rounded up.
And in Orange County, California, dozens of immigrants have signed powers of attorney authorizing relatives and friends to pick up their children from school and access their bank accounts to pay their bills in the event they are arrested by immigration agents.
Around the country, President Donald Trump's efforts to crack down on the estimated 11 million immigrants living illegally in the U.S. have spread fear and anxiety and brought about major changes in how people go about their daily lives.
In El Paso, Texas, Carmen Ramos and her friends have developed a network to keep each other updated via text messages on where immigration checkpoints have been set up.
She said she also is making certain everything she does is in order at all times. She checks her taillights before leaving the house to make sure they are working. She won't speed and keeps a close eye on her surroundings.
"People are hunkering down because they are afraid," said Roberto G. Gonzales, assistant professor of sociology at Harvard University whose research focuses on immigrant and Latino youth.
The unease has been building for months but intensified in recent weeks with ever-clearer signs that the Trump administration would jettison the Obama-era policy of focusing mostly on deporting those immigrants who committed serious crimes.
The administration announced Tuesday that any immigrant in the country illegally who is charged with or convicted of any offense, or even suspected of a crime, will now be an enforcement priority. That could include people arrested for shoplifting or other minor offenses, or those who simply crossed the border illegally.
Some husbands and wives fear spouses who lack legal papers could be taken away. And many worry that parents will be separated from their U.S.-born children.
Dozens of immigrants have been turning up at an advocacy group's offices in Philadelphia, asking questions like, "Who will take care of my children if I am deported?"
An organization in Austin, Texas, that runs a deportation hotline said it normally would receive one or two calls every few days. After recent immigration raids, the phone rang off the hook.
In Long Island communities like Hempstead and Brentwood, immigrants now see the simple act of walking to the store as a task that could destroy their lives. One store owner who didn't want to be identified says his immigrant customers have been staying away, worried that federal agents are waiting on the street to arrest them.
"People are living in genuine terror over the last 24 hours," said immigrant advocate Patrick Young, who says he hears that terror in phone calls that have poured in in the hours since the Trump administration issued its immigration guidelines.
In Los Angeles, immigrants have been attending know-your-rights workshops but also calling in to report they're afraid to pick up their children from school, said Jorge-Mario Cabrera, a spokesman for the Coalition of Humane Immigrant Rights of Los Angeles.
Immigrants in the Chicago area have said they are scared to drive, and some are even wary about taking public transit. When Chicago police and federal authorities conducted regular safety checks on a train line earlier this month, many assumed it was an immigration checkpoint.
Word spread so quickly on Twitter and among activist groups that Chicago police issued a statement assuring immigrants, "You are welcome here."
In the Bronx, Dominguez, a college student who is in the U.S. with permission under the Obama administration policy for people who entered the country illegally as children, is looking into what she needs to do to raise her American-born brother and sister, ages 6 and 11, if their parents are deported. They are in the U.S. illegally.
Now, when Dominguez goes out, she tells the others where she is going, with whom, and when she will be home, and expects the same from her parents and siblings. If someone is late getting home, she said, "we start calling."
Many of Long Island's 70,000-plus undocumented immigrants are just unsure of what to do next.
"'Should I go to work?' They're afraid of sending their children to school. And this is a real form of fear our communities are facing right now," said immigrant advocate Gaby Castillo.
Theo Liebmann, the head of Hofstra's law schools deportation clinic, and others are vowing a legal and political fight against deportations. But the battle, they admit, could be an uphill one.
"In the past, we have always said, 'Don't panic.' We're not saying that right now."