The reason: to weigh in on President Donald Trump's agenda, and the potential of the new Congress to reshape government.
A Kentucky woman named Rose Mudd Perkins laced into Senate Majority Leader Mitch McConnell on Tuesday, raising vanishing coal jobs, health care reform and poverty among other things. She ended with a crack about McConnell's treatment of Sen. Elizabeth Warren. She left, apparently, unsatisfied.
Perkins appeared on CNN the next day and continued to outline her frustration with politicians. She told CNN's Brooke Baldwin about her personal struggles and the issues in her community and said she didn't believe people's voices were registering at the congressional level.
Immigrants and Muslim people concerned
One frequent topic of discussion at these town halls is the President's words and actions with regard to immigrants and Muslim people. In at least one case, a Muslim immigrant raised his concerns with a senator.
"I'm a Muslim, who's going to save me here?" asked Zalmay Niazy, who said he worked with the US armed forces in Afghanistan, at a town hall with Sen. Chuck Grassley.
Seen (and probably also heard)
People have come bearing signs. Some have a specific message or a warning, but many signs that dot the crowds just show a simple sign of agreement and disagreement so participants can indicate their feelings on different issues.
Lock down the vote
Angry constituents regularly pledged to bring down their members of Congress in upcoming elections -- even years down the line.
Then there's New Jersey
New Jersey Rep. Leonard Lance, well, he had a time.
From women 'in my grill' to 'having fun'
Rep. Dave Brat, a Virginia Republican, was recorded complaining about being confronted, saying at the time: "Since Obamacare and these issues have come up, the women are in my grill no matter where I go."
He had long since come around by the time he had a town hall on Tuesday
, when he said, "I like having debate, spirited conversation -- if you can have a conversation."
Asked on Tuesday about a tense event he held, Rep. Jason Chaffetz said
people at his town hall "intended to bully and intimidate" him.
He had earlier in the month said the angry voices at his town hall were from paid protesters, but the protesters said
they were real people, motivated to do this out of concern, not money.
Trump himself has repeatedly said protesters were paid and questionable.
White House press secretary Sean Spicer detailed this accusation in the briefing room.
A different tack
Other Republicans have chosen not to accuse the people at their town halls of being paid or otherwise illegitimate.
Rep. Mark Sanford of South Carolina waded through questions inside and out of his town hall.
Rep. Scott Taylor told CNN at his Monday town hall: "That may be happening in other districts, but I don't know of any paid protesters here, in this district," Taylor said.
And Sen. McConnell said the protests were "as American as apple pie."
Cotton indicated his willingness to engage with his constituents and walked into a tough event on Wednesday.
People waited in long lines for Cotton at a liberal pocket of the red state.
And when he tried to dodge a determined questioner about Obamacare, the audience erupted
The senator closed out his event by taking a question from a 7-year-old. The boy, Toby, asked about Trump and the GOP prioritizing a border wall with Mexico over public programs, like PBS.
"He shouldn't do all that stuff for just a wall," Toby told Cotton.
With or without you
For the members of Congress who have chosen to forgo town hall events so far, some constituents have opted to hold their own events, taking a page
from Clint Eastwood's book to debate an empty chair -- or suit.
Sharp questions on health care
Tennessee Rep. Diane Black got a question about Obamacare from one teacher, and what the teacher had to say went viral.
Iowa Sen. Joni Ernst faced cries of "shame on you" and "do your job" at the event and as she was filing into a car outside. She faced a number of tough interactions, including this moment on Obamacare.