In a stunning move, U.S. Rep. Lauren Boebert on Wednesday night announced that she plans to run next year for the seat held by retiring fellow Republican Ken Buck in Colorado’s 4th Congressional District, rather than seek re-election in the district she barely won last year.

A Silt Republican serving her second term, Boebert joins a crowded GOP primary field in the heavily GOP neighboring district, which covers Douglas County and parts of Larimer and Weld counties, as well as much of the Eastern Plains.

Buck announced in November that he isn’t seeking a sixth term.

House members don’t have to reside in the districts they represent, needing only to be residents of the state that includes their district.

Boebert won reelection last year by just 546 votes in the Western Slope-based 3rd District, which leans toward Republicans by 9 percentage points. The 4th District, which is more favorable toward Republicans, prefers GOP candidates by 27 points, according to a nonpartisan analysis prepared by Colorado’s redistricting commission.

In 2022, Boebert came within 546 votes of losing to Democratic nominee Adam Frisch, who is seeking a rematch in next year’s election.

Boebert is facing two primary challengers in the 3rd CD — Grand Junction attorney Jeff Hurd and Russ Andrews, a largely self-funding candidate from Carbondale.

In the new district, as many as eight Republicans are already running, including former state Sens. Jerry Sonnenberg and Ted Harvey, state Rep. Richard Holtorf and conservative talk radio host Deborah Flora. House Minority Leader Mike Lynch is expected to jump in the race within days.

Editor’s note: This developing story will be updated.