To the southwest, as many as 15,000 people will leave the Pentagon tomorrow morning and begin the Sept. 11 anniversary Freedom Walk to the Mall. To the east, some 90,000 more bodies will converge on FedEx Field to watch the Washington Redskins kick off their regular season. In the middle of it all, the annual Black Family Reunion is expected to draw hundreds of thousands to the Mall, and Robert F. Kennedy Memorial Stadium will host more than 25,000 fans for an important Washington Nationals game.

Gridlock, thy name is Sunday.

The migration of thousands by car, train and foot poses a significant challenge for the region's transportation network. Metro could experience the bulk of the congestion because the Blue Line connects to all of the events. It is the first time Redskins and Nationals home games have fallen at the same time on the same day and the first real test of whether football fans will take Metro in large numbers.

"There are quite a number of events, but I think they're pretty discrete and therefore, hopefully, manageable," said Bill Rice, spokesman for the D.C. Department of Transportation.

Metro will run nearly as many cars as they do on weekdays, allowing trains to pass every five or six minutes through downtown between 7 a.m. and 6 p.m. Extra trains will run at the end of both games.

During the America Supports You Freedom Walk, sponsored by the Department of Defense, motorists can expect delays between Northern Virginia and the Mall. The strictly secured march begins at the Pentagon's south parking lot at 10 a.m., travels on Route 27, over the Arlington Memorial Bridge and onto Independence Avenue SW, culminating on the Mall with a concert by country singer Clint Black.

Only people who preregistered by yesterday afternoon will be allowed to walk. Four-foot-high snow fencing and the full force of the U.S. Park Police will keep others off the route.

A number of roads along the path will be closed to traffic from 7 a.m. to 1 p.m., including the northbound ramp from George Washington Memorial Parkway to Memorial Circle, eastbound Independence Avenue from 23rd Street SW to the west-east turnaround and westbound Independence Avenue from the west-east turnaround at 17th Street NW to Rock Creek Parkway.

On the Mall between Seventh and 14th streets, the Black Family Reunion will celebrate its 20th anniversary today and tomorrow with pavilions featuring arts and crafts, ethnic foods, health screenings and financial counseling. Chaka Khan, the Lissen Band, Mary Mary, Kirk Franklin and the Greater Mount Calvary Sanctuary Choir will perform. The event is open from noon to 8 p.m. both days.

Football fans can travel by Metro to the Morgan Boulevard Station that opened in the Landover area at the end of last season. About 4,000 fans used it to attend the final Redskins game. But that was before fans were familiar with the service, and the game had smaller attendance.

"We really don't know what ridership will be Sunday for the Redskins," said Metro spokesman Steven Taubenkibel, who noted that about 12,000 to 15,000 people take Metro to Nationals' games.

Redskins officials hailed Metro as a convenient option: Fans can take the Orange Line to the Landover Station and catch a $5 shuttle to the game or take the Blue Line to Morgan Boulevard and walk a mile.

Beyond the new station, Redskins spokesman Karl Swanson said fans should expect little difference in their transportation routine around FedEx Field. To some, who have paid $25 to park in Redskins cash lots only to wait in bottleneck traffic on a shuttle bus before arriving at the field, this might not be welcome news.

"Last year, it was a pain. Not even so much getting in as getting out," said Sean Sanford, 32, a season-ticket holder and moderator of the fan Web forum

For the fan in search of free parking, the options are dwindling this season. Last year, some parked free in the Morgan Boulevard station's 500-space lot, but this season, Metro will charge $25 to park there.

Another erstwhile haven for the thrifty was Landover Mall, where fans used to park free and walk on Redskins Road to games. That route was temporarily thwarted by a Prince George's County policy blocking pedestrians from Redskins Road. After fans won a lawsuit challenging the policy, foot traffic was allowed last November. But the owners of Landover Mall quickly began to charge $15 to park there. This season, the price at the 2,000-space lot will rise to $20, said Jay Weitzman, president of Park America, which runs the lot.

And the Jericho City of Praise church will continue its policy of requiring a Redskins parking permit to use its lots near the stadium, said Bobby Henry, a minister.

"Nothing is free, even in our business -- the church business -- it's not free," he said. "Salvation is not free."

Redskins fans wait in line last year at the Landover Metro station to catch a bus to FedEx Field. Metro has since added another stop near the stadium.