At the conclusion of Inauguration Day, the White House will be home to President-elect Donald Trump.
Interested in Donald Trump?Add Donald Trump as an interest to stay up to date on the latest Donald Trump news, video, and analysis from ABC News.
But on the last night before Trump will call 1600 Pennsylvania Ave home, he is expected to spend his final night as president-elect at a lesser-known address just across street at 1651 Pennsylvania Avenue.
"It’s a very small part of the day but a very important part of day," said White House Historical Association curator John Botello, who explained how the house plays a role in kicking off a "new era" in presidential history.
In a tradition dating back to Jimmy Carter, the president-elect spends the eve of his inauguration at the presidential guesthouse. Some president-elects have stayed at the house for longer, such as Carter, who stayed in the house starting in December ahead of his inauguration.
Role in Inaugural Ceremonies
One of the first official inaugural day ceremonies will take place at Blair House when the president-elect signs a new guestbook there.
Botello says the act is an important symbolic diplomatic gesture. "That will sort of open the door for their administration in terms of diplomacy," Botello said.
With each new administration, Botello explained, a new guestbook is begun. And the president-elect is the first to sign the new book.
In addition to the official guestbook signing, the president-elect often uses the space at the Blair House to make finishing touches to his inaugural address and rehearse his speech.
Once the president-elect departs the Blair House, he will attend a private church service at the historic St. John's Church located across Lafayette Square from the White House.
Later in the morning, President Barack Obama and first lady Michelle Obama will receive President-elect Trump and incoming first lady Melania Trump at the White House for tea and a small reception, according to the White House.
From there, the president and president-elect will ride together in the motorcade up Pennsylvania Ave. to the Capitol for the swearing-in ceremony.
How the Blair House Became the President's Guesthouse
The original house known today as the Blair House was built in the 1820s by the first surgeon general of the U.S., Dr. Joseph Lovell. But the house would take its lasting name from subsequent owner Francis Preston Blair, a close confidant to President Andrew Jackson who bought the house when he moved to Washington in an effort to sway public opinion in President Jackson's favor as the editor of the pro-Jackson Globe newspaper.
The Blair House remained a private home for more than a century until it was purchased by the federal government in 1942 to serve its current purpose as a presidential guesthouse.
Before that time, Botello said it was common for presidential guests to stay on the residence floor of the White House.
The change was prompted by one frequent houseguest in particular: Sir Winston Churchill.
The British prime minister stayed at the White House with such frequency during World War II that his visits drove President Franklin D. Roosevelt, at the urging of first lady Eleanor Roosevelt, to establish a space outside the White House.
"He was known to appear in the middle of the night in this bathrobe, trying to disturb the president for late night chats, and so first lady Eleanor Roosevelt talked to the president and they decided they needed a guest house separate from the White House," Botello said. "The story goes that she stopped Sir Winston Churchill from entering [the president's bedroom] one night and said the president needs rest tonight. And for all we know, that could have been the final call for it being time to purchase a house separate from the residence."
Since 1942, the Blair House has continually served as a guesthouse for heads of state and dignitaries visiting from overseas.
Beyond the frequent visits of Churchill, other notable guests include Queen Elizabeth II, French General Charles de Gaulle, Nelson Mandela and the Emperor of Japan.
The Blair House even served temporarily as the president's primary residence during a major renovation of the White House. From 1948 and 1952, President Harry S. Truman made the Blair House his primary residence and office.