Students, teachers, parents and survivors of mass shootings have been streaming into the Washington area ahead of the March for Our Lives, an anti-gun-violence demonstration that could draw hundreds of thousands of protesters Saturday.

They’re arriving in buses, planes and their own cars.

And on Friday, they participated in potluck dinners, tailgate parties, sign-making events and live concerts throughout the city on what District officials have described as one of the busiest weekends the city will see this year — thanks, as well, to the National Cherry Blossom Festival, which begins Sunday.

The march, billed as a youth-led movement spearheaded by student survivors of school shootings, has galvanized many area families, businesses and organizations to lend their support. Families have opened their homes to visitors. Solidarity “sibling marches” have been planned throughout the region and across the nation.

The main March for Our Lives demonstration is scheduled from noon to 3 p.m. Saturday, and due to the expected crowd size, organizers warned, the protest might be less of a march down Pennsylvania Avenue and more of a standing-room-only rally.

Musical performances by Ariana Grande, Common, Miley Cyrus, Jennifer Hudson, Vic Mensa and Broadway performers Lin-Manuel Miranda and Ben Platt will be projected onto 20 giant video screens along the protest route.

As many as 500,000 people are expected to attend March for Our Lives in downtown D.C. on March 24. (Claritza Jimenez/The Washington Post)

In between, rally-goers will hear from about 20 speakers — all of whom are under 18.

Deena Katz, president of March for Our Lives, declined to specify who will be speaking, citing safety concerns. Several of the speakers will be students from Washington-area schools who have been affected by gun violence.

Because the march could draw hundreds of thousands of students, many of them also under 18, officials said they have taken extra care to ensure the safety of protesters.

The Department of Homeland Security, working with D.C. police and the mayor’s office, set up a system to notify attendees of any security issues, warnings or detours. (Text “March 24” to 888-777 to sign up.)

Medical tents staffed by volunteers will line the protest route, doubling as emergency reunification points should groups get separated. Water will be available to protesters and food trucks will be allowed to line up nearby.

“As the young men and women from Parkland, Florida, have been preparing for Saturday’s event, the District has been preparing to keep them safe here in Washington,” Mayor Muriel E. Bowser (D) said this week.

The event will be held along Pennsylvania Avenue NW from 12th Street to Third Street, where the main stage will be. Participants will be subject to security, including bag checks, before entering the rally area.

D.C. Police Chief Peter Newsham asked for patience from participants.

He advised visitors to avoid driving, noting that Metro will begin running at 7 a.m. with frequent trains akin to a rush-hour schedule.

“Be prepared for road closures, increased traffic and parking restrictions,” he said. “It is safe to say that generally getting around in our city, starting in the early-morning hours of Saturday, March 24, will likely be more challenging than most other Saturdays here in the District.”

Several groups have designated rallying points where they will meet before heading downtown.

Among those is Mobilizing MSD Alumni, an organization of former students who banded together in the wake of the school shooting last month in Parkland, Fla.

The school never had an alumni association, with most former students at Marjory Stoneman Douglas High staying connected through social media.

Then the shooting happened.

“When it became clear that the students were organizing and speaking out, our mission became to support them and what they’re doing,” said group founder Judith Danovitch, 39, a Class of 1996 graduate. “And that’s meant helping them with this march — helping with logistics and money and making sure that any Stoneman Douglas student who wants to go to Washington is able to go.”

As of Friday, the group had raised more than $100,000 to bring about 575 students and chaperons to the District.

Organizers said Delta Air Lines donated two planes for Stoneman Douglas students and teachers who will arrive in the District early Saturday and return to Florida that night, so unchaperoned students will not need to worry about a place to stay.

The graduates are participating in more than just the march. Some attended an alumni-only happy hour or a show called “Stay Amped: A Concert to End Gun Violence” at a concert hall in Southwest Washington.

“I think for so much of us, to be this involved has been really meaningful,” Danovitch said. “We’re not just alumni in mourning. From the very beginning, we wanted to do something for our school, for these students.”

Bowser and other city officials will host a pre-event rally at 9 a.m. at Folger Park on Capitol Hill. Survivors of other mass shootings are also expected to attend.

Brandon Wolf, a survivor of the 2016 mass shooting at Pulse nightclub in Orlando, said he will attend the march as a representative of the Pulse victims, including his friend Christopher “Drew” Leinonen and Leinonen’s boyfriend, Juan Guerrero.

“I don’t think this conversation is just about schools,” Wolf said. “It’s about: The current generation is fed up with lawmakers who have done nothing on this issue regardless of which community has been affected. Students, LGBT people, people of color. This issue is intersectional.”

Marches and rallies that force survivors to relive those horrible moments can trigger strong emotional reactions, Wolf said. Several organizations will be available to assist survivors of violent crimes and rally participants who need support.

“It’s so important to remember that while these teenagers are giving us hope and inspiring us and we want to rest everything we have on their shoulders, they’re also kids who have been through something horrific,” Wolf said. “Something they will never forget.”

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