What shuts down during a shutdown

Congressional authorization for federal spending for many nonessential services expired at midnight EST Friday. Here is how a partial shutdown affects government services:

National parks: Golden Gate National Recreation Area, Point Reyes National Seashore, Yosemite National Park and other parks would make site-by-site decisions as to what to close. While many open-air sites would remain open, most visitor services would cease. The Presidio in San Francisco would remain mostly open.

Benefits: Social Security and Medicare would continue, though there could be delays in payments if a partial shutdown drags on. Help desks and phone support may be reduced.

Food assistance: Aid programs are not expected to be immediately affected, though some could be curtailed in a prolonged shutdown. The programs include the Special Supplemental Nutrition Program for Women, Infants and Children, food stamps, Meals on Wheels and school lunches.

Housing assistance: The federal Department of Housing and Urban Development expects to continue as normal in the short run, though a long deadlock in Washington could mean delays in housing contracts and mortgage assistance.

Worker safety: Federal occupational safety inspectors could scale back reviews.

Federal courts: Northern California court offices would remain open and fully funded through at least Feb. 9.

Military: The military services would continue operations, though many civilian Defense Department employees could be furloughed.

Mail: Post offices would be open and the mail would be delivered.

Airports: Security checkpoints would be staffed, and air traffic controllers would stay on the job. Congress: Members would continue to be paid.