Republican state Reps. Richard Holtorf and Mike Lynch have qualified for the primary ballot in Colorado’s 4th Congressional District by submitting a sufficient number of petition signatures, state election officials said.

Holtorf and Lynch join U.S. Rep. Lauren Boebert and former U.S. Senate candidate Deborah Flora in the June 25 GOP primary for the Eastern Colorado seat formerly held by Republican U.S. Rep. Ken Buck, who resigned in March.

The primary field could grow in coming weeks: Five additional Republican candidates are awaiting review of petitions they submitted by last month’s deadline.

A special election to fill the remainder of Buck’s term will take place at the same time as the primary. The Republican nominee in that election, former Parker Mayor Greg Lopez, isn’t running in his party’s primary, while the Democrats’ special election nominee, Trisha Calvarese, is one of four candidates seeking the Democratic primary nomination.

The 4th CD covers Douglas County, parts of Larimer and Weld counties and Colorado’s Eastern Plains.

For Colorado congressional candidates, it takes 1,500 valid signatures from fellow party members to make the ballot. Holtorf submitted 2,612 signatures, and 1,866 were passed muster, the Secretary of State’s Office said. Lynch turned in 3,977 signatures, and 1,596 were deemed valid.

Candidates can get on Colorado’s primary election ballot by gathering petition signatures, going through the parties’ caucuses and assemblies, or by taking both routes.

While Lynch only went the petition route, Holtorf opted for the hybrid approach. At last week’s congressional district assembly in Pueblo, he finished in fourth place, with 15% of the delegate vote – above the 10% threshold for candidates who are also petitioning.

Boebert won top-line designation on the primary ballot at the assembly by finishing ahead of the other hopefuls, with 40% of the vote, after earlier qualifying by petition. Boebert moved into the solidly Republican 4th CD in January from the more competitive 3rd Congressional District she’s represented for two terms.

Holtorf, an Army veteran and third-generation cattle rancher and farmer from Akron, boasted to Colorado Politics that he was the only Republican running for the seat who relied entirely on volunteers to circulate his petitions.

“I had a 100% volunteer group of circulators and petitioners from 13 counties in the 21-county district, who went to every county in the district and solicited over 2,500 signatures,” Holtorf said. “This is a true grassroots effort, and every volunteer should be very proud of their efforts because they believe in Holtorf for Congress.”

He added that the district’s constituents “should be very pleased that the most qualified candidate can now be a choice for veteran leadership for Colorado.”

Earlier this week, Holtorf called on Colorado GOP Chairman Dave Williams to resign after the state party formally endorsed Boebert, under recently adopted party rules that permit state Republicans to take sides in primaries.

Lynch, a West Point graduate and small business owner from Wellington, told Colorado Politics he was grateful for the volunteers who helped him get on the ballot.

“It’s a grassroots effort to get on via signatures instead of going through the party process,” he said, adding, “The party that exists right now is actually the establishment.”

In a statement, Lynch said he looks forward to the primary campaign.

“For far too long, politicians on both sides of the aisle have ignored the will of the people and pursued their own agendas at the expense of everyday Americans,” Lynch said.

“I am running for Congress because I believe in the resilience and potential of the American people. Our best days are ahead and, with the right leadership, we can course-correct starting today.”

Ike McCorkle, the Democratic nominee who ran against Buck in 2020 and 2022, qualified for the primary ballot this week by petition. Other Democrats, including Calvarese, were seeking slots in the primary Thursday night in an online convention.