Democrat Saira Rao on Monday submitted petitions to the secretary of state’s office to secure a spot on the 1st Congressional District primary ballot – becoming the second congressional candidate in Colorado to turn in signatures.

“This campaign is about giving everyone a seat at the table and making Colorado a progressive leader in national politics,” Rao said in a statement. “I’m so grateful to everyone who helped make this happen, and I look forward to a robust primary and healthy debates on healthcare, criminal justice reform, and getting corporate money out of the Democratic Party.”

Rao, a co-founder of the media and publishing company In This Together Media, is one of three Democrats mounting a primary challenge against U.S. Rep. Diana DeGette, a Denver Democrat serving her 11th term.

This year, an unprecedented 21 candidates are circulating petitions in Colorado’s seven congressional districts, as well as dozens of statewide and legislative candidates.

To make the June 26 ballot, congressional candidates must collect 1,000 valid signatures from fellow party members registered in their district. A spokeswoman for Rao’s campaign said she turned in just over 1,700 signatures.

“So many unaffiliated voters wanted to sign our petition,” said Jordan Bresson, the Rao campaign’s field director and a former organizer with Conservation Colorado. “Only registered Democrats are allowed to sign, but it’s safe to say we met more than a few hundred independents who are voting for Saira in June.”

For the first time this year, unaffiliated voters will be able to cast ballots in the Democratic or Republican primary without having to sign up with either party.

“We’re keeping in touch with every person we interacted with during the petition drive,” said JoyAnn Ruscha, Rao’s campaign manager, in a statement. “We feel awesome about the positive feedback we got in the field and we’re excited about participating in Colorado’s first open primary.”

Republican Darryl Glenn, an El Paso County commissioner running in a primary against six-term U.S Rep. Doug Lamborn in the 5th Congressional District, was the first candidate for Congress in Colorado to get petitions in to election officials. Last week, Glenn learned he was the first candidate in the state to qualify for the ballot.

The deadline to submit signatures is March 20. Candidates were able to start circulating petitions on Jan. 16.

Two other Democrats, David Sedbrook and Michelle Hudson Hale, have also filed to run in the 1st District, which includes Denver, Glendale, Englewood, Sheridan, Cherry Hills Village and parts of Jefferson County in the southwest metro area.

Three Republicans are campaigning for the seat – John Field, Jeremiah Vialpando and 2016 GOP nominee Casper Stockham.