WASHINGTON — The Senate adjourned Friday night without reaching a stopgap agreement to fund seven government agencies, and a partial government shutdown began at midnight.

The sticking point: the president’s determination to secure $5 billion in funding for a southern border wall — likely his last chance to secure wall funding before Democrats gain control of the House.

Talks were set to continue over the weekend, with no sense of how long the lapse in funding might last. Here's what to expect in the meantime:

Only certain agencies will close

Congress has already funded 75 percent of the government through September 2019 — which means that many major departments like Defense, Veterans Affairs, Energy and Education will remain open and fully functioning.

The shutdown will primarily impact seven agencies which have not been funded and run out of money at midnight Friday: Homeland Security, Transportation, Commerce, Interior, Agriculture, Housing and Urban Development and Justice. Other independent agencies like NASA, the FDA, the EPA and the IRS would have to furlough most of their employees.

Those departments and agencies will continue to be staffed by “essential” employees who would work without pay until the shutdown ended. All other “non-essential” employees will be sent home without pay. More than 420,000 employees will be required to work without pay and an additional 380,000 would be sent home, according to a fact sheet compiled by Senate Democrat staffers.

Correctional officers, FBI agents, U.S. Marshals, TSA employees, Border Patrol officers, Coast Guard employees, Forest Service firefighters and Weather Service forecasters are all expected to continue working without pay.

National parks, which closed during a 16-day government shutdown in 2013, would remain open, but park visitor centers would likely close. While parks will remain open, staff will not perform maintenance and upkeep — like snow removal — to make sure they remain accessible.

Smithsonian museums and the National Zoo in Washington would use remaining funds to stay open and pay employees until January 1. It is unclear if they will remain open past New Year's Day.

The post office will also remain open, meaning any last-minute Christmas gifts won’t be affected by a shutdown.

J. David Cox, the president of the American Federation of Government Employees, called for lawmakers to avoid a shutdown so federal employees would not have to work without pay.

“Our members are asking how they are supposed to pay for rent, food, and gas if they are required to work without a paycheck,” Cox said in a statement. “The holiday season makes these inquiries especially heart-wrenching.”

Trump will stay in Washington

White House press secretary Sarah Sanders said Thursday that the president will not fly to Mar-a-Lago in Florida for his scheduled holiday vacation while the government is shut down.

It is unclear how many members of Congress will remain to continue negotiations. Many representatives who lost their elections last month have already gone home, and appear in no rush to return over the Christmas holiday. Other senators also flew home after voting on Wednesday, but returned to the Capitol to vote on House resolution. Friday's procedural vote lasted 5 hours and 18 minutes — what appeared to be the longest vote in modern Senate history — in part because senators from Western states needed more time to fly to Washington.

Senate Majority Leader Mitch McConnell, R-Ky., said last week that the Senate might have to labor through Christmas.

"Unless we approach all this work in a highly collaborative, productive way and take real advantage of unanimous consent to expedite proceedings, it is virtually certain that the Senate will need to be in session between Christmas and New Year's in order to complete this work," McConnell said.

What about government benefits?

Social Security has its own funding source and will issue its usual checks. Medicare and Medicaid should still be able to pay out benefits, although it's possible customer service and various administrative duties might be impacted by furloughed employees.

Families who receive food stamps will still get their January benefits even if the shutdown continues into the new year. Other nutritional programs, like WIC and school meals, will be able to continue operating on remaining funding.