When was the last US government shutdown? How long did it last? A brief history of gridlock

The federal fiscal year ends in four days and a government shutdown is looming. With Congress still divided over spending, the clock is ticking on a compromise and without one, D.C. may be forced to power down.

If the stalemate over funding is not broken by Oct. 1, the U.S. will enter its 22nd government shutdown in the last five decades. Beyond the walls of Congress, millions of Americans would feel the effects as various government-run programs shutter.

Here's a primer on the federal government shutdown, and a brief history of its precedent in American politics.

What is a government shutdown?

A government shutdown occurs when there is a lapse in funding, according to the Center for American Progress. The federal fiscal year runs from Oct. 1 to Sept. 30. If Congress does not agree on spending and pass a federal budget by Oct. 1, the government is forced to shut down.

During a government shutdown, all federal agencies and services that officials do not deem "essential" must stop working. Essential services include the U.S. Postal Service and Medicare and Social Security services.

"Non-essential" work, however, must pause operations, affecting many federal employees and millions of Americans. A shutdown can mean thousands of federal workers furloughed, government food assistance benefits delayed and national parks closed.

When was the last government shutdown?

The last government shutdown lasted from Dec. 22, 2018 to Jan. 25, 2019. Spanning 35 days, it was the longest government shutdown in U.S. history.

It was also the third federal shutdown to occur during the Trump administration; the first lasted three days in January 2018, and the second lasted only a few hours in February 2018.

List of government shutdowns in the U.S.

Over the last five decades, there have been 21 federal shutdowns:

• 1976: Under President Gerald Ford. Lasted for 11 days.

• 1977: Under President Jimmy Carter. Lasted 12 days.

• 1977: Under President Carter. Lasted eight days.

• 1977: Under President Carter. Lasted eight days.

• 1978: Under President Carter. Lasted 17 days.

• 1979: Under President Carter. Lasted 11 days.

• 1981: Under President Ronald Reagan. Lasted two days.

• 1982: Under President Reagan. Lasted one day.

• 1982: Under President Reagan. Lasted three days.

• 1983: Under President Reagan. Lasted three days.

• 1984: Under President Reagan. Lasted two days.

• 1984: Under President Reagan. Lasted one day.

• 1986: Under President Reagan. Lasted one day.

• 1987: Under President Reagan. Lasted one day.

• 1990: Under George H.W. Bush. Lasted four days.

• 1995: Under President Bill Clinton. Lasted five days.

• 1996: Under President Clinton. Lasted 21 days.

• 2013: Under President Barack Obama. Lasted 17 days.

• 2018: Under President Donald Trump. Lasted three days.

• 2018: Under President Trump. Lasted several hours.

• 2019: Under Trump. Lasted 35 days.

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This article originally appeared on USA TODAY: When was the last government shutdown? This isn't DC's first rodeo