Transportation Security Administration, air traffic control and border patrol officers would stay on duty.
Entitlement programs: Social Security, Medicare and Medicaid checks would get sent out.
Courts: The Supreme Court would be mostly unaffected, and federal courts could continue to operate for two weeks.
Obamacare exchanges: The Affordable Care Act's state-run exchanges would open Tuesday as planned.
The federal school lunch program is expected to stay intact through at least the end of October.
Unlike in previous shutdown scenarios, the State Department would have the ability to continue issuing visas and passports due to a recent budget change. Some applications could still be delayed, however.
What Gets Closed
National parks, museums and the National Zoo would be closed to the public.
Environmental Protection Agency administrator Gina McCarthy warned last week that a government shutdown would mean "that EPA effectively shuts down."
The Special Supplemental Nutrition Program for Women, Infants and Children (WIC) would run out of money.
The Food and Drug Administration would still execute recalls of food and drugs, but would be unable to maintain much of its usual oversight.
The Energy Department would mostly shut down, aside from a few offices, including the one charged with oversight of the country's nuclear arsenal.
The Securities and Exchange Commission would continue to post corporate filings to its website, but staff members wouldn't be able to review them.
Most Department of Homeland Security operations would not be affected, but its e-Verify program, which allows businesses to check the legal immigration status of its employees, would shut down.
The National Institutes of Health would still be able to conduct some research and provide services to current patients, but would not be able to accept any new patients.
The Centers for Disease Control and Prevention would have "significantly reduced capacity" in responding to outbreaks and processing laboratory samples, but would "continue minimal support to protect the health and well-being of U.S. citizens."