The demonstrations, which have generally been larger than those that took place in Cleveland during the RNC, have followed in the wake of what has been a tumultuous week for Democrats highlighted by an email leak which appeared to show efforts by the party to impede the campaign of Sen. Bernie Sanders, and the resignation of Debbie Wasserman Schultz, the chair of the party.
The protests have resulted in multiple people being detained, police said. No one has been arrested.
Some marchers carried banners that read "Hillary for Prison," and signs with pictures of Trump and Clinton that read "Either Way, Wall Street Wins." A group of protesters carried a giant float shaped like a joint, urging government to "end the racist drug war."
Demonstrators targeted delegates walking on the other side of a dividing line to enter the Wells Fargo arena, and one observer described the mood as "furious."
In interviews, protesters expressed anger and frustration about the management of the Democratic Party, and about the nomination of Clinton.
"A lot of people feel like their banging their heads against a wall," a protester wearing a Bernie sticker on his shirt told ABC News in reference to attempts to reform the Democratic Party. "Money corrupts politics."
"I understand the sentiment never Trump, but there are a lot of people here who are never Hillary," he added.
He called the alleged efforts of the DNC to stop Sanders "collusion" and "sad to see."
One woman told ABC News she would be voting for Sanders "regardless" of whether his name was on the ballot.
A man in a Bernie shirt told ABC News that he would be voting for Green Party candidate Jill Stein.
"That's too bad," he said, regarding Sanders' endorsement of Clinton.
The atmosphere of division was felt both inside and outside the Wells Fargo arena. During the invocation, hosted by interim chair Marcia Fudge, boos echoed through the hall, and chants of "Bernie" followed the mention of Clinton's name.