The National Park Service, working directly with the Presidential Inauguration Committee, is making elaborate preparations to host what may very well be the biggest crowd ever to gather in Washington, D.C.

On January 20 as many as four million people are expected to descend on the National Mall & Memorial Parks to witness Barack Obama’s inauguration as the 44th President of the United States. Hordes of spectators will cram the National Mall to witness the swearing-in ceremony that will take place on the steps of the U.S. Capitol. Vast numbers will line Pennsylvania Avenue to see the ensuing Inaugural Parade, an event that moves the new president, physically and symbolically, from the Capitol, home of the legislative branch of the federal government, to the White House, home of the executive branch.

Having huge numbers of Americans and people from all over the world personally witness the peaceful transition of power in the world’s most important democracy is a proud tradition. However, it is also a gargantuan logistical headache for the National Park Service. If the projections of three-four million visitors prove accurate, the crowds will dwarf the previous largest events in the history of the National Mall by three or four times. And no matter the size of the crowd, a huge amount of work will have been done before, during, and after the event by National Mall & Memorial Parks and the Park Police.

To help everyone get a view, the National Park Service is installing JumboTrons on the National Mall. JumboTrons, big screens that carry a live television feed of the event, were successfully used during the last several Presidential inaugurations.

As in the past, large numbers of people will camp overnight on the Mall to lay claim to the places offering the best views. Well, at least they’ll be competing for the best spots not reserved for the approximately 240,000 people with invitations to the inauguration (mostly in the form of free tickets distributed by senators and representatives). People who don’t have reservations and aren’t willing to camp on the Mall will have to depend on binoculars and the JumboTrons. Extra JumboTrons are also planned for the parade route to help those who won't have a front-row view.

All of the best places along the Pennsylvania Avenue parade route will be taken long before the inauguration ceremony commences. Since it’s not possible to attend both events, officials are cautioning visitors to “pick one.”

The National Park Service is used to dealing with big crowds in our nation’s capital. Lyndon Johnson’s inauguration drew an estimated 1.2 million spectators (the most ever for an inauguration), and at least 1 million people gathered on the National Mall for the nation’s Bicentennial celebration on July 4, 1976.

Nevertheless, crowds of the size anticipated for the upcoming inauguration are several orders of magnitude bigger than any that the Park Service has dealt with before. One might reasonably wonder whether three or four million people can be safely accommodated on the National Mall, Pennsylvania Avenue National Historic Site (yes, Pennsylvania Avenue is actually a national park - and a separate Unit of the National Park System), and President’s Park (which includes not only the White House and the Ellipse, but also Lafayette Park, which will have a news media reviewing stand). So far, officials say “yes,” but some special arrangements will be necessary.

One of the important adjustments is the relocation of the parade staging area. For previous inaugurations, certain sections of the National Mall near the Washington Monument were reserved for use as a staging area for the Inaugural Parade. This year that space will be needed for spectators and will not be available for parade staging. As of this writing the NPS hasn’t announced where the new staging area will be located.

The Park Service is apparently considering allowing crowds to fill in not just the National Mall from the Capitol Building to the Washington Monument, but also the grounds of the Washington Monument (which sits on an elevated hilltop) and perhaps even the Parks and Monuments area stretching all the way to the Lincoln Memorial. All told, the corridor from the U.S. Capitol to the Lincoln Memorial stretches some two miles and encompasses about 300 acres (nearly half a square mile). Although it's unlikely that the space will be packed with people (since it will be impossible to view the inauguration from most places behind the Washington Monument), the area will be available if it's needed.

Security is naturally a major concern. The U.S. Secret Service is serving as the lead federal law enforcement agency for this event, which has been declared a National Special Security Event (NSSE), but the NPS has important responsibilities. The United States Park Police, an administrative unit of the NPS, is working with the Secret Service and numerous other participating agencies to help create what is designed to be “a “seamless security plan that will create a safe and secure environment for President-elect Obama and his family, other dignitaries, event participants, and the general public.”

Traveler tips and caveats, no extra charge: Whether you are attending the inauguration or the parade, get there as early as you can manage. That's the only way you'll have a chance at a decent vantage point. If you're attending the inauguration, try to get a spot near the center of the Mall so your view won't be obstructed by one of the JumboTrons. Bring good binoculars. At best, you'll be trying to view a six-foot tall figure from a quarter-mile mile or more away. (Many people don't realize that it's a quarter of a mile from the top of the Capitol steps to the other side of the fountain/pool in front of the Ulysses S. Grant Memorial where the National Mall begins.) At this time, maps and checkpoint information have not been released for the 2009 Inaugural. There will be bag checks at certain checkpoints, and you can expect good crowd control directing you to them. It's likely that certain Metrorail Stations will be closed, including the Smithsonian/National Mall Station and the National Archives/US Navy Memorial Station. MetroRail will direct inauguration attendees to get off at the appropriate spots.

Postscript: There will be no rest for the weary after the inauguration is over. Just two days later, on Thursday, January 22, opponents of the U.S. Supreme Court Decision in Roe vs. Wade will participate in the annual March for Life, which includes a rally on the National Mall near the Washington Monument, followed by a march down Constitution Avenue to the U.S. Supreme Court Building. At least 100,000 people are expected to participate in the event.