Many recalled their experiences inside.
Democrat Congresswoman Pramila Jayapal said she feared for life as the mob pounded on the doors of the House chamber.
"I remember thinking that I may not make it out of there alive and that we may not have seen our democracy survive. But the thought that I keep with me to this day a year later, is that we saved democracy. And when I say we I am not talking about we, members of Congress, I am talking about we the people."
Four people died in the hours-long chaos after Trump urged his supporters to march to the Capitol and "fight like hell."
One police officer died that day, while four others have died since by suicide.
Criminal charges have been brought against more than 700 people linked to the riot.
Congressman Jamie Raskin, also a Democrat, urged those at the vigil to pay tribute to the Capitol officers.
"I decided I'm going to observe the first anniversary of January 6th by celebrating the people who defended our lives and our democracy."
On Thursday, U.S. President Joe Biden accused Trump of spreading a "web of lies" to undermine U.S. democracy .
Even still, Trump remains highly popular among Republican voters and is working to shape the field of GOP candidates in this year's midterm elections.
