In another key race, Republican U.S. Rep. Ryan Zinke of Montana won reelection to the House, again defeating challenger Monica Tranel. The victories continue Republican control in a state where the GOP also enjoys a decisive majority in the Legislature.

The Republican incumbent fended off a challenge from Ryan Busse. Democrats held the Montana governorship for 16 years, until Mr. Gianforte’s first election in 2020.

The race was rated as "solid Republican" by the Cook Political Report, with most polls showing Gianforte with a roughly 20% lead.