Social Security: Is a mandatory program, which means checks will continue to be mailed.
Mail delivery: The post office will remain open and your mail will be delivered.
Travel: Transportation Security Administration officers and Customs and Border Protection agents would remain on the job, which means air travel should be mostly unaffected.
Passports: The State Department's passport services remain open. Passports will be issued, but some applications may be delayed.
Courts and justice: Federal courts would continue normal operations for the time being because they have a three-week cushion of funding.
Military: The active-duty military will remain on the job, and military operations would continue. Training missions may be curtailed.
National parks: Interior Department states that it will work to keep national parks and other public lands "as accessible as possible."
Congress: Congress would continue to operate.
Federal agencies: Most federal agencies would be closed, like the Department of Education, the EPA, and the IRS, although some essential functions will continue to operate.
Museums: The Smithsonian Institution states that its museums in Washington, D.C., as well as the National Zoo, would remain open for the weekend, but will close on Monday if the government shuts down.