‘The city has a lot of practice at cleaning up after these sorts of events,” Mr. Tangherlini said.

He said it would take at least a month to disassemble the two reviewing stands at the White House where President Obama and members of the news media had watched the parade. One stand is four stories tall, with a balcony.

Hosting the inauguration cost the city $47 million, according to city officials who have already received $15 million from Congress and promises for the rest later.

Early estimates of the crowd ranged as high as two million, while the National Park Service and Mayor Adrian M. Fenty put the figure at 1.8 million. City officials said the number could be higher if the people standing on the Mall, along the parade route and farther into the surrounding neighborhoods were counted.

Satellite images of the swearing-in ceremony suggested, however, that the actual size of the throng might have been smaller, according to experts who reviewed the images. Nonetheless, most agreed it was probably the largest crowd ever at an inauguration.

The National Park Service has not given official estimates of crowds in more than a decade, complying with a Congressional order to stop doing so after a controversy over how many people attended the Million Man March in 1995. Estimates then varied from 400,000 to more than a million.

But David Barna, a Park Service spokesman, said the agency was making an exception this year because of the historic nature of the inauguration and the public demand for a crowd estimate.

Subway officials said ridership set a record Tuesday, with 973,285 trips by 7 p.m. The figure broke the record of 866,681, which was set Monday on Martin Luther King’s Birthday.