Six of Arizona's nine U.S. House races this year will include at least one televised debate, giving voters a chance to see congressional candidates face off in what is shaping up to be a historic midterm election.

Arizona has at least one race, the Tucson-based 2nd Congressional District, that is expected to be fiercely contested and perhaps four others where both parties hope for a change in recent fortunes.

A debate for the state's open U.S. Senate seat has not yet been scheduled.

The one-hour debates in the House races will offer an up-close appraisal for voters, in most cases ahead of early balloting, which begins Oct. 10. Most of the debates are held at 5 p.m. on Arizona PBS (Channel 8) and will be moderated by Ted Simons of "Arizona Horizon" and Yvonne Wingett Sanchez of The Arizona Republic.

3rd Congressional District

The first debate is Tuesday, Sept. 18, for the 3rd Congressional District and will feature Democratic incumbent Raúl Grijalva against Republican Nick Pierson.

RELATED:Congressional District 3: Pierson wins GOP nomination, to face Grijalva

Grijalva is seeking a ninth term in office for the district that includes part of Tucson and spans most of the state’s border with Mexico up to the West Valley. Pierson has worked as a financial adviser.

6th Congressional District

On Friday, Sept. 21, attention turns to the 6th Congressional District race between Republican incumbent David Schweikert and Democratic challenger Anita Malik. Schweikert is trying to win a fifth term in the Scottsdale-based district.

RELATED:Anita Malik wins Democratic primary, now faces David Schweikert

Schweikert is a member of the tax-writing House Ways and Means Committee and Malik works in technology and communications and has embraced a relatively liberal policy agenda on worker benefits, job creation and inequality.

2nd Congressional District

The debate for the open 2nd Congressional District seat is scheduled for Thursday, Sept. 27, on Tucson PBS affiliate KUAT-TV.

That race pits Democrat Ann Kirkpatrick against Republican Lea Marquez Peterson for the seat currently held by U.S. Rep. Martha McSally, a Republican running for the Senate. Many nonpartisan analysts view the seat as leaning to Kirkpatrick and it is considered essential for Democrats to retake the House.

Kirkpatrick spent three terms representing northeastern Arizona in Washington and ran for the U.S. Senate in 2016. Last year she moved to Tucson, where her new district is one of the nation's most evenly divided between the parties and will have its fourth different representative since 2012.

Marquez Peterson, CEO of the Tucson Hispanic Chamber of Commerce, narrowly won the GOP nomination last month and is hoping to keep the seat McSally won easily in 2016.

9th Congressional District

On Tuesday, Oct. 2, candidates in the 9th Congressional District square off.

That race features Democrat Greg Stanton, the former mayor of Phoenix, and Republican Steve Ferrara, a radiologist who has worked in the Veterans Affairs hospital system.

RELATED:Congressional District 9: Ferrara wins race to face Stanton in November

That seat is currently held by U.S. Rep. Kyrsten Sinema, a Democrat now running for the U.S. Senate. The district runs from north-central Phoenix between Interstate 17 and State Route 51 down to cover portions of Tempe, Mesa, Chandler and back into Ahwatukee Foothills in south Phoenix. It includes Arizona State University.

1st Congressional District

On Monday, Oct. 8, Democratic incumbent Tom O'Halleran will face Republican challenger Wendy Rogers in the debate for the 1st Congressional District that spans northeastern Arizona, from the Utah border down to the outskirts of Tucson.

RELATED:Congressional District 1: Wendy Rogers wins, will face Tom O'Halleran

O'Halleran is seeking a second term in Washington while Rogers makes her fourth bid for Congress.

8th Congressional District

Finally, on Friday, Oct. 19 — nine days after the beginning of early voting — candidates in the 8th Congressional District meet for a rematch of their close special election in April.

Republican incumbent Debbie Lesko, who replaced disgraced former Rep. Trent Franks after his December resignation, will again debate Democratic challenger Hiral Tipirneni, a physician and cancer research advocate.

That district covers the West Valley, from New River south to Goodyear and from Peoria west past the Sun cities.

RELATED:5 takeaways from the 8th District congressional primaries

Two of Arizona's Republican incumbents, Reps. Andy Biggs and Paul Gosar, have not scheduled debates.

Biggs, a House freshman, faces Democrat Joan Greene, a businesswoman and advocate for rescue animals, in the 5th Congressional District race. The district covers the East Valley from south of Loop 202 down through Mesa to Sun Lakes and Queen Creek.

Gosar, who is seeking his fifth term in Congress, is running against Democrat David Brill, a doctor and businessman. That district covers the far northwestern corner of the state and reaches down to Yuma and Florence.

Gosar, who has made a string of controversial remarks over the past two years, refused to debate, citing The Republic's involvement.

"It publishes fake 'fact checks' and routinely ignores Congressman Gosar's accomplishments and instead writes almost exclusively negative stories about Gosar," his chief of staff wrote. "The Republic is not a neutral debate arbiter."

There is no debate in the 7th Congressional District because U.S. Rep. Ruben Gallego, a Democrat, has no Republican challenger as he seeks a third term. His district runs from southern Glendale to downtown Phoenix and reaches to South Mountain Park.

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