Atkinson is the brother-in-law of Tulsa Mayor Dewey Bartlett, but he has been involved in the campaign of Bartlett’s re-election opponent, G.T. Bynum.

Bridenstine, who filed Wednesday, said he intends to keep his pledge not to seek more than three terms.

“Four years ago I filed to run for Congress for the first time, promising the people of the 1st District that I would work every day to restore Constitutional integrity, fiscal responsibility and national security,” Bridenstine said. “My promise to the people of Oklahoma remains unchanged.”

Jackson, 30, has been campaigning since shortly after leaving the Army last year. A native of Oologah and U.S. Military Academy graduate, Jackson positions himself to the right of Mullin. He has attacked the two-term incumbent’s votes on budget agreements that Bridenstine opposed.

In interviews, Jackson has said he sees himself as similar to Bridenstine politically.

U.S. Sen. James Lankford has announced he will file Friday.

Filings Thursday were down from Wednesday’s near-record pace, but still higher than usual. More than 65 candidates turned in their paperwork, bringing the two-day total to 320 and far exceeding the 2012 total for all three filing days.