But different agencies estimate crowds that vary in number by the hundred thousand.
According to WRC-TV, planners expect no more than 900,000 people to attend Trump's weekend events.
The District of Columbia's Department of Homeland Security and Emergency Management is expecting 800,000 to 900,000 people to attend the swearing-in ceremony and the inaugural parade, WRC-TV reported. The news organization says the U.S. Armed Forces Joint Task Force National Capital Region, which provides support for the ceremonies, is expecting 800,000 people. The Joint Congressional Committee on Inaugural Activities, which plans and executes all ceremonies, is expecting 700,000 to 750,000 people.
Destination D.C., which manages and promotes the city as a tourism and special events destination, estimates about 1 million people will be in the city for inaugural festivities.
It's unclear if those numbers include protesters.
"Anybody who is just saying there were a million people there without saying what method they used, that's just public relations being offered," Arizona State University journalism professor Steve Doig told WRC-TV. "Take any estimate with a grain of salt. What you need to do is look carefully at how the estimate was done and how transparent the group who did it is about their methods."
An estimated 800,000 and 250,000 people showed up for Bill Clinton's 1993 and 1997 inaugurations respectively. About 300,000 people attended the inauguration for George W. Bush in 2001, and an estimated 400,000 people were recorded for his 2005 inauguration.