Generally, if the government shuts for budgetary reasons, all but “essential” personnel are furloughed and are not allowed to work.
USCIS: USCIS is a fee-funded agency so if the government shuts down, it is generally business as usual. The exception to this is those programs that receive appropriated funds – E-Verify, the EB-5 Immigrant Investor Regional Center Program, Conrad 30 J-1 doctors, and non-minister religious workers. As announced by USCIS on January 20, 2018, those programs may be suspended or otherwise impacted.
DOS: Visa and passport operations are fee-funded and should not be impacted by a lapse in appropriations, but operating status and funding will need to be monitored closely. If visa operations are affected, consular posts will generally only handle diplomatic visas and “life or death” emergencies.
CBP: Inspection and law enforcement personnel are considered “essential.” Ports of entry will be open; however, processing of applications filed at the border may be impacted.
ICE: ICE enforcement and removal operations will continue, and ICE attorneys will typically focus on the detained docket during a shutdown. The ICE Student and Exchange Visitor Program (SEVP) offices are unaffected since SEVP is funded by fees.
EOIR: Immigration court cases on the detained docket will proceed during the lapse in congressional appropriations while non-detained docket cases will be reset for a later date when funding resumes. Courts with detained dockets will receive all filings but will only process those involving detained dockets. Courts with only non-detained dockets will not be open and will not accept filings.
DOL:Is NOT impacted by this government shutdown. On September 28, 2018, President Trump signed a minibus appropriations bill funding DOL through the end of September 30, 2019.