Oregon voters elected Democrat Kate Brown to a second term as governor in Tuesday's midterm elections.
With Brown's lead growing late into the night, challenging Republican Knute Buehler conceded the race.
Republicans had believed that Oregon provided one of their best chances to flip a Democratic governor's seat in a year when Democrats generally have been making greater gains.
Democrats on Tuesday flipped governor's offices in at least four states — Illinois, Kansas, Michigan and New Mexico.
Republicans entered Election Day holding 33 governor's offices and two-thirds of the state legislative chambers.
Reporting from The Associated Press also contributed to this article.