Former Pinal County Sheriff Mark Lamb has officially entered the race for Arizona’s 5th Congressional District, making this a primary to watch heading into 2026.

The seat, currently held by Congressman Andy Biggs, became available after Biggs announced his intention to run for governor. Lamb, who rose to national prominence through his outspoken defense of border security and appearances on reality TV, filed his statement of interest with the Arizona Secretary of State’s Office this week.

Lamb, often dubbed “America’s Favorite Sheriff,” built a strong law-and-order reputation during his terms as Pinal County Sheriff. His office became known for its emphasis on border enforcement, anti-fentanyl initiatives, and visible community policing efforts. He also gained national media exposure through programs like Live PD and 60 Days In, which helped make him a recognizable figure beyond Arizona.

Lamb joins what is expected to be a crowded GOP primary. Former NFL kicker Jay Feely, a Gilbert resident, entered the race earlier this year, positioning himself as a family-focused conservative with a strong media background. Former State Representative Travis Grantham, who represented much of the East Valley, Alex Stovall, who previously ran for the CD4 seat, and newcomer Daniel Keenan, who is self-funding his race.

Early polling from NextGen P shows Lamb with roughly 54 percent support among likely Republican voters, placing him well ahead of other prospective candidates — a reflection of his high name recognition and broad support among the party’s grassroots.

Arizona’s 5th Congressional District covers the East Valley suburbs, including Gilbert, Queen Creek, and parts of Mesa, extending into northern Pinal County. It’s one of the state’s most reliably Republican districts, where Biggs consistently won by double-digit margins.

With Biggs vacating the seat, the GOP primary will likely determine the district’s next representative.

Lamb previously ran for U.S. Senate in 2024 but lost in the Republican primary to Kari Lake. Despite that defeat, he has maintained strong grassroots support and widespread popularity among conservatives, bolstered by his high-profile law enforcement background and visibility in national media.