Shouting "Not my president!" and carrying placards that read "I did not elect hate for president," some 300 people marched in Baltimore.
Protests were also taking place in Chicago, Denver, Dallas and elsewhere.
"We are just showing that this is going to be the next four years, it'll be four years of resistance," Kaila Philo, a 21-year-old student, told The Baltimore Sun.
She said she had created an event on Facebook for her friends that ended up attracting thousands.
Earlier on Thursday, demonstrators -- mostly students who skipped classes -- also marched in San Francisco, Los Angeles and other cities.
Some 1,000 students, most of them high-schoolers, marched through San Francisco's financial district toward City Hall chanting "Not my president!" and blocking traffic. Some also carried placards that read "Trans Against Trump" and "Make America Safe For All."
"We are protesting because we want to stand up for our rights and we deserve to be heard," Pamela Campos, 18, told the San Francisco Chronicle.
"Donald Trump is just racist. He's attacking all the immigrants, all the Muslims. I saw all my classmates crying yesterday."
Students held walkouts in several other northern California cities, including Napa and Hayward.
In Los Angeles, several hundred students marched at the University of California campus carrying placards that read "Dump Trump" and "Love trumps hate."
"Initially, I accepted his election but yesterday when I saw Hillary's concession speech, I couldn't avoid crying," Daisy Rivera, 24, told AFP of the Democratic candidate Hillary Clinton.
"I can't believe we have that racist, xenophobic, misogynist elected president."
'Traumatic election'
In New York, some 200 anti-Trump protesters gathered at Manhattan's Washington Square Park.
Similar demonstrations that attracted tens of thousands of people took place in various cities on Wednesday
Protests are also planned over the weekend.
The demonstrations have been peaceful overall despite some arrests and police in riot gear deployed in heavy numbers in several cities.
Los Angeles Mayor Eric Garcetti lauded the protests while urging the demonstrators to stay off freeways and not vandalize property.
"This was a traumatic election," he told a news conference. "There's plenty of division, and there's finger-pointing in both directions, but there were things that were said that were not partisan, about women, about our Muslim brothers and sisters, about immigrants."
Trump's rhetoric about immigrants, Muslims and refugees outraged many during the election campaign. Around a dozen women have also accused the real estate billionaire of sexual misconduct.
Demonstrators chant in front of a fire they lit in protest against President-elect Donald Trump outside the City Hall building in Los Angeles, California, USA Source: AAP
Professors at several universities across the country cancelled classes or delayed tests on Wednesday to allow students to "cope" with the election outcome.
At Cornell University in New York, where students held a "cry in," one professor scrapped her lecture for fear she would "break down" before students.
A University of Michigan psychology professor postponed an exam saying his students appeared clearly upset.
