WASHINGTON (AP) — The new U.S. House majority is still undetermined, but one thing was clear by Thursday night: The majority party's margin will be narrow.

With a number of races closer than expected, here is a look at some notable contests that had not yet been called.

Colorado 3rd District

Few people, except maybe voters in western Colorado, would have expected Republican Lauren Boebert to be in such a tight race in the rural, mountainous district.

The fiery conservative and cable news figure known for her devotion to 2nd Amendment gun rights — and from Rifle, Colorado, no less — was narrowly ahead of Democrat Adam Frisch in the 3rd District, which covers 26 counties across the expansive southwestern half of the state.

This region of ski resorts, national forests and ranches, coal towns and desert mesas, has long bred low-key politicians. Elected in 2020, Boebert broke that mold as a fierce loyalist to former President Donald Trump, questioning the legitimacy of the 2020 election results.

California 47th District

Two-term Rep. Katie Porter, part of the 2018 class of freshman women who helped Democrats capture the House, was locked in a competitive fight with Republican Scott Baugh in a Southern California district Republicans had high hopes of capturing.

Porter was facing Baugh, a former state representative, in a district that includes Orange County, where Republicans once held sway but that has become more Democratic.

President Joe Biden carried the district in 2020, but Republicans placed it in the heart of their target list this year, expecting low approval for Biden to help lift Baugh. Though still hopeful here, Republicans failed to defeat 2018 Democrats running in seats Biden won in Virginia, Pennsylvania, Michigan, Minnesota, Kansas and elsewhere.

Maryland 6th District

In Maryland's rolling, wooded western panhandle, Republicans had a shot at picking up a seat held by two-term Democrat David Trone, the multimillionaire founder and co-owner of Bethesda-based alcohol retailer Total Wines & More.

Trone, elected in 2018 and re-elected in 2020, received roughly 60% of the vote in both previous elections, but was trailing Republican state Delegate Neil Parrott, also from Bethesda.

Republican and Democratic campaign committees, as well as independent race rating organizations, had viewed Trone as reasonably safe. But Parrott was ahead narrowly with only a small portion of the vote outstanding.

Trone notably spent $13 million of his own running in the 8th District primary in 2016, setting the mark for the most expensive, self-funded race at the time. Trone lost to Jamie Raskin, who has been re-elected twice in that district.

Maine 3nd District

Two-term Democrat Jared Golden was leading in Maine's 2nd District, a sprawling swath of forests, lakes and small towns covering the majority of the Northeast state.

Golden, a member of the freshman class of 2018 that gave Democrats the majority, was a prime target for Republicans.

And while Golden was running ahead of Republican Bruce Poliquin, he was expected to fall short of the 50% needed to win. Because the state uses ranked choice voting, the race will move to a second round on Nov. 15, when the third-place finisher, independent Tiffany Bond, will be eliminated and voters’ second choice picks will be factored in a new count.

Golden, whose support for guns rights plays well in the overwhelmingly rural region, was facing Poliquin in a rematch, having defeated him for re-election to the seat four years ago.

Despite the district's smaller media markets, the two parties and outside groups combined to spend more than $26 million, second only to Michigan's 7th District, which includes the Detroit and Lansing media markets and where both sides combined spent more than $27 million.

California 13th District

Republican John Duarte and Democrat Adam Gray were locked in a tight race in this open seat in California's Central Valley.

The district, including Fresno, is a mix of middle- and working-class communities and includes a commuter corridor to San Francisco, where gasoline prices have been particularly important as a campaign issue given the number of residents who travel regularly to the Bay area.

A win by Gray would not help Democrats pick up seats because the incumbent is Rep. Josh Harder, who moved to a more Democratic-performing adjacent district.