The Trump administration issued an interim final rule effective April 11, 2025, requiring certain noncitizens to register with the Department of Homeland Security (DHS) and carry proof of registration at all times. Many noncitizens are already registered because of documents DHS previously issued, such as a work permit. For noncitizens who are implicated by this new rule, there is risk of detention, deportation, and criminal prosecution. Below, we address some frequently asked questions on this new registration rule. We recommend that pro bono attorneys working with NIJC clients review these FAQs and counsel their client accordingly.