No such raids have been documented so far, and the Department of Homeland Security has declared schools off limits. But under the Trump administration, immigration policies have changed sharply and without much warning. Districts say they want to be prepared.

“If you’re sitting there in math class wondering if someone is going to burst through the door and pick you up, you’re not going to be learning math well,” said William Clark, chief operating officer of the New Haven Board of Education in Connecticut. “The kids should not be worried about this. They’re here to learn.”

For the moment, much of what school systems are offering is guidance, and whether it is written by the Connecticut public university system, the New York City Education Department or the State of Virginia, many of the recommendations are similar. Schools often say student information must not be shared without a court order or subpoena. They instruct that if an Immigration and Customs Enforcement officer comes looking for a student, the school officials should demand to see a warrant and review it carefully to find out what exactly it permits.

“The law does provide protections for students, and there are limitations of what law enforcement can do,” said Attorney General Eric T. Schneiderman of New York. “We’re doing our best to fill in the background and to tell them that students have a lot of rights.”

Many guidance documents also offer advice on how to prepare for raids that might happen outside school.