The 1940 United States presidential election in Oregon took place on November 5, 1940, as part of the 1940 United States presidential election. Voters chose five representatives, or electors, to the Electoral College, who voted for president and vice president.

Malheur County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 31,571. Its county seat is Vale, and its largest city is Ontario. The county was named after the Malheur River, which runs through the county. The word "malheur" is French for misfortune or tragedy. Malheur County is included in the Ontario, Oregon Micropolitan Statistical Area, which is also included in the Boise Combined Statistical Area. It is included in the eight-county definition of Eastern Oregon.