Seven thousand were demonstrating, some set fires, a police car was vandalized and one officer was injured.
Anti-trump protesters first gathered at Frank Ogawa Plaza Wednesday night and the crowd grew to some 7,000. They took over Webster Street in Downtown Oakland and marched. All was peaceful.
Police surrounded them and the march splintered into smaller groups at Washington and 8th street. Suddenly, a Trump piñata was up in flames and flash bangs were going off in the streets.
Several buildings were vandalized and there were reports of looting and building fires throughout Wednesday night. Police have made arrests.
The protest started with people who are sincerely concerned about the views and actions of president elect Donald Trump. People chanted, "Go away Donald Trump," as they marched down Oakland streets in response to the results of the presidential election.
PHOTOS: Protests spark in Bay Area after 2016 election
Jumoke Hinton Hodge said as a newly elected Oakland school board member she's concerned about students.
"Many of our teachers had to be with students who are scared to death of what may happen, Latino children, Muslim Arabic children," Hodge said.
Others worried about the message sent to their daughters.
"Two girls going to sleep thinking they were waking up to the first woman president and woke up to a nightmare instead. We had to show them that there was still hope today. That there are people believe that they're the future and that we have hope," said Eleza and Hil Jaeger.
The Oakland Police Department estimated about 6,000 marched, most peacefully until people started spray painting, smashing windows, and starting fires. One officer was injured.
There were other Midwest protest marches in Omaha, Nebraska, and Kansas City, Missouri. Hundreds also gathered in Providence, Rhode Island, and Portland, Maine.
News from other protests:
RELATED: Thousands protest in New York; 65 arrested
Hundreds of protesters gathered near Philadelphia's City Hall despite chilly, wet weather. Participants - who included both supporters of Democratic nominee Hillary Clinton and independent Vermont Sen. Bernie Sanders, who lost to Clinton in the primary - expressed anger at both Republicans and Democrats over the election's outcome.
In Boston, thousands of anti-Trump protesters streamed through downtown, chanting "Trump's a racist" and carrying signs that said "Impeach Trump" and "Abolish Electoral College." Clinton appears to be on pace to win the popular vote, despite losing the electoral count that decides the presidential race.
In Chicago, where thousands had recently poured into the streets to celebrate the Chicago Cubs' first World Series victory in over a century, several thousand people marched through the Loop. They gathered outside Trump Tower, chanting "Not my president!"
Chicago resident Michael Burke said he believes the president-elect will "divide the country and stir up hatred." He added there was a constitutional duty not to accept that outcome.
Police said that an estimated 1,800 to 2,000 people participated in the Chicago protests. Police reported five arrests, including two for obstructing traffic, but said there were no major incidents.
Los Angeles demonstrators also beat a Trump piñata and sprayed the Los Angeles Times building and news vans with anti-Trump profanity. One protester outside LA City Hall read a sign that simply said "this is very bad."
Late in the evening several hundred people blocked one of the city's busiest freeways, U.S. 101 between downtown and Hollywood.
City News Service reported that 13 people were arrested as officers in full riot gear walked the protesters off the freeway.
By 1:30 a.m., the freeway was clear of demonstrators but lanes remained closed for cleanup.
Marchers protesting Trump's election chanted and carried signs in front of the Trump International Hotel in Washington, D.C.
Media outlets broadcast video Wednesday night showing a peaceful crowd in front of the new downtown hotel. Many chanted "No racist USA, no Trump, no KKK."
Another group stood outside the White House. They held candles, listened to speeches and sang songs.
OREGON AND SEATTLE:
In Oregon, dozens of people blocked traffic in downtown Portland, burned American flags and forced a delay for trains on two light-rail lines.
Hundreds massed in downtown Seattle streets.
Many held anti-Trump and Black Lives Matter signs and chanted slogans, including "Misogyny has to go," and "The people united, will never be defeated."
Five people were shot and injured in an area near the protest, but police said the shootings and the demonstration were unrelated.
The Associated Press contributed to this report