Congress and President Donald Trump were unable to agree on a stopgap spending measure by the Friday midnight deadline, forcing the federal government to shut down for the first time in five years.

Although essential government operations will remain open, many federal employees will be placed on furlough.

“The first people hit will be those 800,000 government employees that won’t be getting paid,” says Marina Whitman, a professor of public policy at the University of Michigan’s Gerald R. Ford School of Public Policy. 

The shutdown isn’t expected to have any immediate impact on most Americans, as long as it lasts only a few days. The Army will not lay down its weapons, and Social Security and Medicare payments will still go out.

But the longer the government remains closed, the more problematic it becomes, Whitman says. Here’s how you could be affected:

Travel

As workers are furloughed, national parks and monuments may close. That means that if you plan to visit Yellowstone National Park or the Lincoln Memorial, for example, you may have to delay your trip.

The good news, though, is that the Interior Department has said that even if there is a shutdown, it will work to keep national parks and other public lands accessible. Even if some parks are closed, the impact will likely be less than if the shutdown happened during warmer months. Yellowstone National Park, for example, receives about 95 percent fewer visitors in the winter than it gets in the summer.

If the shutdown lasts for more than a few days and you need to renew or apply for a passport, you could run into problems. Without workers, the State Department would have to stop processing applications.

Foreign nationals should also expect delays when it comes to processing work and travel documents. Although the State Department will continue to process visas during a shutdown, that function is partially funded through appropriations, so it could suffer disruptions.

Taxes

Although tax day is months away, tax season began in early January. For those already starting to review tax documents, the government shutdown could complicate the process because you may not be able to reach anyone at the Internal Revenue Service for assistance.

Taxpayers, however, may not notice the impact that much. IRS budget cuts in recent years have already reduced assistance consumers might get from the agency.

If you need to complete the W-4 Form, which determines your tax withholding allowance, or the W-9 Form, which you generally submit if you are self-employed, you’ll probably have to wait out the shutdown. 

Healthcare

Though Medicare or Medicaid will continue to operate, the biggest concern is how the shutdown might affect the Children’s Health Insurance Program (CHIP), which provides low-cost health coverage to children in families that earn too much money to qualify for Medicaid.

Funding for the program ran out in October, and though Congress provided $2.85 billion in December, that money is running out, says Don Taylor, a professor at Duke University’s Sanford School of Public Policy. The government shutdown now makes it unlikely that states would be able to get their share of any funding, according to the Centers for Medicare & Medicaid Services.

General Government Assistance

Depending on how long the shutdown lasts, Americans could run into other problems as well, such as getting up-to-date information from government websites. Applications for, say, grants would also halt as federal agencies such as the National Institutes of Health and the National Education Association stop processing applications.

Home energy assistance programs, which help low-income Americans pay for heating during the cold winter weather, could start to run out of money. The same is true of Temporary Assistance for Needy Families, which administers federal grant programs.

If you need to sign up to get Social Security or Medicare or if you are applying for a mortgage, you may now have to be patient. “By law, any mortgage loan approval is subject to review by the mortgage lender of the borrower’s federal tax returns,” says Tim Ross, CEO of Ross Mortgage, based in Troy, Mich. Because the lender depends on IRS employees to provide and confirm those tax returns, it will have to wait until they are back at work.