Vocal opponents to President Trump's nominee for the nation's high court chanted near the steps of the courthouse; some of Kavanaugh's supporters demonstrated as well.
The controversy over Kavanaugh's nomination is coming to a head now as the Senate prepares to vote on his nomination, likely in the next two days.
Trump nominated Kavanaugh on July 10 but decades-old accusations of sexual assault created drama and logistical hurdles late in the confirmation process.
Protesters have been coming to Washington in waves since last week, when both Kavanaugh and Christine Blasey Ford, one of Kavanaugh's accusers, testified before the Senate Judiciary Committee in hearings that seen around the world.
Ford accused Kavanaugh of sexually assaulting in the early 1980s when both were teenagers.
Two other women also accused Kavanaugh of sexual misconduct.
Kavanaugh has repeatedly denied the accusations, which became the focus of an FBI investigation. Senators are reviewing the results of the probe ahead of a cloture vote Friday.
A vote on Saturday can come as early as Saturday afternoon.
Against the backdrop of senators reviewing the results of the investigation and charges that the probe was limited in scope, some protesters appeared to be arrested, surveillance footage showed.
Local police had not released arrest numbers by Thursday afternoon.
Actress Amy Schumer was shown in line appearing to prepare to be arrested in the Senate building amid the protest.
Senate Majority Leader Mitch McConnell, who supports Kavanaugh's nomination, addressed the stream of protesters from the Senate floor Wednesday, talking about how Republicans are coming into contact with protesters in their offices.
"I want to make it clear to these people who are chasing my members around the hall here or harassing them at the airports or going to their homes. We're not being intimidated by these people. There is no chance in the world they’re going to scare us out of doing our duty," McConnell said.
One memorable and arguably pivotal moment with a protester came when one woman, identifying herself as a sexual assault survivor, confronted Sen. Jeff Flake in an elevator as he was on his way to vote in the Senate Judiciary Committee, the day after the Ford and Kavanaugh hearings.