Police warned the crowd multiple times to clear the intersection of High and State streets in downtown Columbus to make way for traffic, according to ABC News affiliate WSYX.
Video posted on Twitter around midnight showed police officers in gas masks spraying the crowd that gathered near the Ohio Statehouse brandishing anti-Trump signs and chanting.
A representative for the Columbus chapter of the group Socialist Alternative told ABC News that it organized the rally and promoted it on its Facebook page.
"Several of our members were part of the group who were pepper-sprayed, but many other groups showed up in solidarity," Kyle Landis, one of the event's organizers, told ABC News on Tuesday morning.
The Columbus Police Department did not immediately respond to ABC News' requests for comment on the matter.
The event, called Resist Trump: Rally for the 99 percent, was advertised to start Monday at 6:30 p.m. local time. The group said it is against Trump's executive order on immigration as well as his push to move forward on the construction of the Keystone XL and Dakota Access oil pipelines.
His controversial executive order on immigration temporarily bars entry into the U.S. for people from seven predominantly Muslim countries and has been meet with protests in several cities.
The demonstrators began gathering on Monday evening at City Hall as Columbus Mayor Andy Ginther announced that the city will continue to accept refugees regardless of their immigration status.
"Our immigrant population is part of the fabric of what makes Columbus so vibrant," he said in a statement. "They are our neighbors. We must not turn our backs on them — now or ever."
Columbus is one of the so-called sanctuary cities that do not always fully cooperate with federal immigration enforcement.
Ginther said he will issue an order of his own this week that will "support the resettlement of refugees to Columbus and prohibit the detention of anyone unless a warrant exists or a criminal violation was observed," according to the city's website.