Washington (CNN) Rep. Paul Cook, a California Republican, announced Tuesday that he will not seek reelection to the House in 2020, adding to the growing number of House Republicans who plan to depart in 2020.

In this July 2017 file photo, Rep. Paul Cook (R-CA) listens to the House Rules Committee Chairman as amendments to the National Defense Authorization Act for approval so it can be debated on the floor of the House in Washington, DC.

Cook will pursue a seat on the San Bernardino County Board of Supervisors, he said.

"Serving in Congress has been an absolute honor, and I'm proud of my numerous victories amid a tough partisan atmosphere. Our high desert needs continued strong leadership at the county level, and I pledge to fight for this area with the same dedication and conviction I've demonstrated my entire career," he said in a statement.

Twelve GOP members have announced they will retire in 2020, and four, including Cook, are leaving to seek different office. Wisconsin Rep. Sean Duffy will also resign at the end of September in order to spend more time with his family ahead of the birth of his ninth child.

Cook, currently in his fourth term, previously served in the California State Assembly and was mayor of Yucca Valley. The Los Angeles Times first reported his plans on Tuesday.

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