Hundreds of students at a Maryland high school walked out of class and into the streets Monday morning to protest Donald Trump’s election as president, a march that gained strength as their peers from nearby schools joined them.

The demonstration involving Montgomery County students was among numerous protests in the Washington area and around the country since Trump’s surprise victory in the Nov. 8 election. Students at Woodrow Wilson High School in the District say they will leave their Northwest school at midday Tuesday, with plans to protest at the new Trump International Hotel a few blocks from the White House.

Students at Montgomery Blair High School streamed onto the school’s football field about 10 a.m. Monday for a walkout that soon turned into a march along University Boulevard. The procession grew larger as it drew students from Northwood and Albert Einstein high schools and headed into Wheaton and downtown Silver Spring.

“Not our president,” some students chanted.

“No hate, no fear, immigrants are welcome here,” others called out.

Students at Montgomery Blair High School left school and marched along a street to protest the election of President-elect Donald Trump. (WUSA 9)

The backpack-clad marchers, flanked by police cars with flashing lights, snarled traffic but found support from many drivers, who honked and flashed peace signs. One group of students said they encountered a Trump supporter who told them to go back to class. Police reported no serious incidents.

Students said the protest was an effort to have their voices heard; because they aren’t old enough to vote, they said, it was the most effective way to raise concerns about the president-elect. Others said they walked out as a show of solidarity with people who felt alienated during Trump’s campaign, including immigrants, Muslims, women and minorities.

“I think we’re trying to show that young people have a voice and we want to be heard,” Olivia Hardwick, 14, a Blair freshman, said as she and others walked down Georgia Avenue.

Blair students talked about their school being diverse — 26 percent of the students are black and 32 percent are Hispanic — and how they believe it is important to stand up for minorities.

Officials estimated that about 1,000 students walked out, about a third of the Blair student body of 2,800; some who joined the protest on the football field went back to classes and did not march.

Sam Rose Davidoff, 15, a sophomore and activist at Blair, said the protest was meant to show that Trump has not won over young people like them. “Although we can’t get represented through voting, we can get represented through protesting,” he said.

Montgomery Blair High School junior Lyla DiPaul, 16, joins other students in a small rally in a parking lot at Westfield Wheaton Mall on their way to downtown Silver Spring marching to protest the election of Donald Trump. (Toni L. Sandys/The Washington Post)

The spark for the protest started at Blair last week and circulated on social media. The school’s principal, Renay Johnson, gave the students permission to gather on the football field but said their absence would be unexcused. Once on the field, many students said they realized there would be little visibility for a protest tucked away on a sports field and decided to head into the streets.

“I feel disappointed that Trump is president,” said ninth grader Jorge Ventura, 15. “I feel anyone, any race, should come here and feel welcome.” Immigrants contribute to American society, he said. “They could cure Ebola, cancer, anything like that.”

Montgomery school officials said students who missed class would be marked with unexcused absences unless their parents provide a note saying they approved the absence. A number of students said they had called their parents and gotten support.

A Montgomery County police spokeswoman said there were no arrests. The marchers dispersed shortly after 1:30 p.m.

Jerry Cave, a Montgomery County Republican activist, criticized the anti-Trump protests, saying they are “exactly what I had anticipated: that immediately upon Donald Trump’s victory, the left would attempt to delegitimize his presidency.”

“High school kids are supposed to be in high school,” Dave said. “I grew up in D.C. with the Vietnam riots going on and we didn’t do that. And believe me, we were every bit as politically engaged as the kids are now.”

The Maryland demonstration came amid a week of similar public displays, mostly in areas where Democrat Hillary Clinton saw significant support at the ballot box.

Berkeley High School students joined other California schools in protest last week, walking to the University of California at Berkeley as a group. About 300 Minneapolis students walked out of five high schools across the city Friday to protest Trump’s election and the Dakota Access Pipeline. They marched into downtown Minneapolis and made their way into various business lobbies, according to the Minneapolis Star Tribune.

Hundreds of students from the Los Angeles Unified School District were out on the city’s streets demonstrating Monday morning, some holding U.S. and Mexican flags and signs that read “Siempre unidos” — always united.

Michelle King, superintendent of the Los Angeles system, said students should limit their protests to non-instructional time.

“For their own safety and to follow the law, they should remain on campus,” King said in a written statement. She said the schools are using assemblies, classroom dialogues and speaking activities to “provide a secure forum for our students.”

“These are important conversations that need to take place,” King said in the statement. “However, it is critical that students not allow their sentiments to derail their education or for their actions to place them in danger.”

Jeanne Theoharis, a professor of political science at Brooklyn College at the City University of New York, said high school students have historically taken to the streets in protests and in some instances have been on the forefront of major civil rights movements. High school students were a key force in a civil rights campaign in Birmingham, Ala., in 1963. One of the cases that led to a U.S. Supreme Court decision to end school segregation stemmed from a high school student strike in Prince Edward County, Va.

Theoharis said the public presence of these students matters because it shows that they believe their voice will be heard and that they can spur change in policies, a belief that she said is a crucial aspect of democracy.

“They see the necessity not to normalize this,” Theoharis said. “They see the necessity to build a resistance and say this is not who we are as a country.”

Protests also broke out during the past week at major college campuses, which often have left-leaning student bodies. Some of those protests morphed into contentious clashes between Clinton and Trump supporters. Protesters at American University in the District, for example, burned flags during a protest last week, an action that led to a shouting match with Trump supporters.

Students at D.C.’s Wilson High School — the biggest high school in the D.C. Public School system — plan to take the Metro downtown on Tuesday, march along Pennsylvania Avenue and stand in front of the Trump Hotel holding hands, according to a widely circulated flier.

Maria Patino, an 18-year-old Wilson senior, said she thinks it’s unfair that Clinton won the popular vote but was not elected president. As an immigrant, Patino said she wants to speak out against Trump’s comments about Mexicans.

“I have been here for three years,” Patino said. “Coming to a country where the culture and language are so different is not easy. I want those who support Trump to understand that we deserve better treatment.”

In an email to the school community Monday morning, Kimberly Martin, Wilson’s principal, emphasizing that the protest was not a sanctioned school event and that students who miss class would receive unexcused absences. Martin also wrote that school administrators and teachers defend all students’ right to peaceful protest and self-expression.

“Wilson Social Studies teachers, and many other teachers, empower students to be inquisitive, informed, and engaged citizens who use critical thinking, inquiry and literacy to prepare for college, careers, and civic life,” Martin wrote in the email. “However, students will be reminded to follow their regular class schedule, as we cannot ensure the safety of any student that chooses to leave the school before dismissal.”

Bill Turque contributed to this report.

This report has been updated.