The closure will "lessen the possibility of individuals illegally accessing the White House grounds", Secret Service spokeswoman Cathy Milhoan said.
There won't be any new physical barriers, and the Secret Service took pains to note that the restrictions won't stop people from viewing or taking photos of the presidential mansion.
The move comes after a series of recent efforts to shield President Donald Trump from public scrutiny.
Visitors can still get themselves into the photo frame with the White House in the background from Lafayette Park across the street, but it won't be same as leaning against the White House fence, within hailing distance of the President. More highly symbolic First Amendment space is gone.
The US Secret Service said it would end public access to a path along the south fence of the White House beginning on Wednesday night. They reported last week that two Secret Service agents on duty that night have been told they will be fired.
In a statement, the Secret Service said the restriction is part of an "ongoing comprehensive review of temporary and permanent security measures at the White House complex".
The U.S. Secret Service said it plans to further restrict public access to areas around the White House, a decision officials announced a month after a man carrying mace scaled the White House fence and was able to roam the grounds.
FILE - In this October 3, 2014 file photo, two women lean against a temporary barrier along Pennsylvania Avenue in front of the White House in Washington. In addition, the agency has announced plans to raise the height of the fence and make it "tougher, taller and stronger", as a spokeswoman put it past year.
In 2014, an armed intruder climbed the north fence of the Obama White House, got inside and all the way to the East Room before security tackled him.
The stretch of Pennsylvania Avenue remains closed to drivers. In either case, the White House is becoming a little more distant from the people.