The 1980 United States presidential election in Illinois took place on November 4, 1980. All 50 states and The District of Columbia, were part of the 1980 United States presidential election. State voters chose 26 electors to the Electoral College, who voted for president and vice president. This would be the last time a Democrat failed to win more than three counties as well as the last time Rock Island County voted Republican, with the county turning sharply to the Democratic party beginning with Reagan's reelection bid and continuing through to the present day.

Rock Island County is a county located in the U.S. state of Illinois, bounded on the west by the Mississippi River. According to the 2020 census, it had a population of 144,672. Its county seat is Rock Island; its largest city is neighboring Moline. Rock Island County is one of the four counties that make up the Davenport-Moline-Rock Island, IA-IL Metropolitan Statistical Area.