The crowd, however, was peaceful, with no immediate reports of arrests or violence.
In addition to the people on the capitol grounds, there was a large group outside the fenced area, which was not under the ban on weapons and is an open carry area. They were chanting "Northam out" and outnumbered the group on the capitol grounds. There was a heavy police presence among this crowd, and law enforcement could also be seen on the rooftops, providing extra security to the area.
Several protesters brandished rifles and held signs extolling gun rights.
"We came unarmed ... this time," one read. "Patriots unite! They ban, we fight," read another.
A petition was circulating calling for Northam's recall, an effort unlikely to succeed given that it would require the signatures of hundreds of thousands of registered Virginia voters to trigger a court process.
Manny Vega of Richmond, who was outside the secured area, said he and his fellow protesters were "here to represent every citizen here that wants to keep the right to bear arms."
Authorities would not immediately give estimates on the crowd size. But some streets surrounding the capitol grounds, several of which were closed ahead of the event, were packed with protesters.
Speakers at the event concluded their remarks around noon, and crowds began dispersing shortly afterwards.
Concerns about threats
People began lining up around 6 a.m. ET to go through security, an hour before gates to the capitol grounds were opened. Security was very thorough, as officers went through bags and made people remove their jackets to be searched despite the frigid temperatures. Law enforcement confiscated items like lighters as people passed into the secured area.
State Capitol Police urged attendees on social media that if they "SEE SOMETHING, SAY SOMETHING," and posted a list of prohibited items.
"The Democrat Party in the Great Commonwealth of Virginia are working hard to take away your 2nd Amendment rights," Trump tweeted late Monday morning. "This is just the beginning. Don't let it happen, VOTE REPUBLICAN in 2020!
According to Northam, law enforcement had learned of credible threats of violence surrounding Monday's rally, made from mainstream and alternative dark web channels used by violent groups and white nationalists outside of Virginia.
Sean Restatter, 22, told CNN on the capitol grounds Monday that the protest was intended to be peaceful.
"There might be far-right and far-left groups that might be out here today, but the vast majority of the message is 'guns save lives' and we believe in the 2nd Amendment," he said.
Right to gun ownership for 'law abiding citizens'
Northam's executive order was quickly challenged in court by VCDL, the Gun Owners of America and three private individuals, who argued that the ban violated their rights under the First and Second Amendments. A judge upheld the governor's temporary ban on Thursday, leading them to file an appeal with Virginia's Supreme Court. On Friday, the Supreme Court of Virginia refused their petition, leaving Northam's ban in effect.
But since winning control of the state legislature in November, Democrats have more successfully advanced gun control measures in the 2020 legislative session.
The Virginia Senate, along party lines, approved several gun measures last week, including background checks for private firearm transfers, limiting gun purchases to one handgun a month and allowing localities to ban firearms in public during a permitted event.
The bills now head to the Virginia House of Delegates.
This story is breaking and will be updated.