The 1980 United States Senate elections were held on November 4, coinciding with Ronald Reagan's victory in the presidential election. The 34 Senate seats of Class 3 were contested in regular elections. Reagan's large margin of victory over incumbent Jimmy Carter gave a huge boost to Republican Senate candidates, allowing them to flip 12 Democratic seats and win control of the chamber for the first time since the end of the 83rd Congress in January 1955. This is one of only five occasions where ten or more Senate seats changed hands in an election, with the others being in 1920, 1932, 1946, and 1958. This is the earliest Senate election with a Senator that is still serving, that being Chuck Grassley of Iowa. This was the largest Senate swing since 1958, and was the largest Republican gain since 1946, when the Republicans also picked up 12 seats. This was also the last time the Senate changed hands in a presidential election year until 2020 when Democrats won control, the last time the Republicans gained control of the Senate in a presidential election year, and the last time Maryland elected a Republican to the Senate. These elections were also the last time the winner of the presidential election had coattails in the senate until 2004. Warren Magnuson, who lost the Washington election, was the most senior United States senator to ever lose re-election until Ted Stevens lost in 2008. Results summary Source: Office of the Clerk Change in composition Before the elections After the elections Gains, losses, and holds Retirements Three Republicans and two Democrats retired instead of seeking re-election. Defeats One Republican and twelve Democrats sought re-election but lost in the primary or general election. Race summary Special elections There were no special elections in 1980. Elections leading to the next Congress In these general elections, the winners were elected for the term beginning January 3, 1981; ordered by state. All of the elections involved the Class 3 seats. Closest races In nineteen races the margin of victory was under 10%. Alabama Incumbent Democrat Donald Stewart decided to run for his first full term, but was defeated in the primary. In November, Republican Jeremiah Denton defeated Democrat Jim Folsom, Public Service Commissioner. Alaska Incumbent Democrat Mike Gravel ran for a third term, but lost in the Democratic primary to Clark Gruening, a former state representative who was the grandson of