Representative Lauren Boebert, the MAGA lightning rod who switched districts in Colorado to avoid being ousted from the House, won a crowded Republican primary on Tuesday in a conservative area of the state, all but ensuring that she will serve another two years in Congress.

Ms. Boebert, a two-term Republican, overcame multiple challengers in the eastern plains of Colorado, nearly guaranteeing that she will prevail over her Democratic rival in November in the solidly red Fourth Congressional District. The Associated Press called the race for her less than half an hour after polls closed as she led by a wide margin.

An outspoken right-wing lawmaker, Ms. Boebert first won her seat in 2020 after upsetting an incumbent Republican in a primary. She made a name for herself with strong pro-gun views, packing a Glock on her hip and encouraging staff at her now closed restaurant to openly carry handguns. In Congress, she has become known for her strident MAGA views and has become entangled in a series of personal scrapes, including being ejected from a Denver theater in a lascivious episode that was caught on closed-circuit camera.

Facing a strong Democratic threat in the sprawling western Colorado district where she was first elected, Ms. Boebert chose to relocate to eastern Colorado to give herself a better chance of remaining in the House — and it appears to have worked.

The seat was vacated earlier this year by Ken Buck, a Republican who left Congress before the end of his term and will be replaced temporarily by Greg Lopez, a Republican former mayor of Parker who won a separate special election on Tuesday. Ms. Boebert did not run in the special election, since that would have required her giving up her current seat, cutting into the thin Republican majority.

Former President Donald J. Trump endorsed her, and her national profile helped her raise significantly more money than her five primary opponents, who split the anti-Boebert vote and enabled her victory despite claims that she was carpetbagging by suddenly changing her residence.

Ms. Boebert narrowly won re-election in her original district in 2022 by just over 500 votes and would have again faced a challenge from Adam Frisch, a Democrat who made the race close two years ago with little outside help. This go-round, he was drawing strong financial support from Democrats who saw a chance to oust Ms. Boebert.

Now, with Ms. Boebert gone, Democrats are hoping to pick up the seat she now holds in the conservative district, which includes high-end ski resorts as well as energy facilities and working ranches. Democrats boosted a right-wing conservative in a crowded primary there, gambling that a far-right Republican might be easier for Mr. Frisch to defeat in November.

But the effort came up short when Jeff Hurd, a Grand Junction lawyer, won the Republican nomination on Tuesday, giving the party establishment the candidate it preferred against Mr. Frisch.