The 1978 United States Senate elections were held on November 7, in the middle of Democratic President Jimmy Carter's term. The 33 seats of Class 2 were contested in regular elections. Special elections were also held to fill vacancies.
The 1958 United States Senate elections were elections for the United States Senate which occurred in the middle of President Dwight D. Eisenhower's second term. Thirty-two seats of Class 1 were contested in regular elections, the new state of Alaska held its first Senate elections for its Class 2 and 3 seats, and two special elections were held to fill vacancies.
The 1952 United States Senate elections was an election for the United States Senate which coincided with the election of Dwight D. Eisenhower to the presidency by a large margin. The 32 Senate seats of Class 1 were contested in regular elections, and three special elections were held to fill vacancies. The Republicans took control of the Senate by managing to make a net gain of two seats. However, Wayne Morse (R-OR) became an independent forcing Republicans to rely on Vice President Richard Nixon's tie-breaking vote, although Republicans maintained a 48–47–1 plurality. Throughout the next Congress, Republicans were able to restore their 49–46–1 majority. This was the third time, as well as second consecutive, in which a sitting Senate leader lost his seat.
The 1946 United States Senate elections were held November 5, 1946, in the middle of Democratic President Harry S. Truman's first term after Roosevelt's passing. The 32 seats of Class 1 were contested in regular elections, and four special elections were held to fill vacancies. The Republicans took control of the Senate by picking up twelve seats, mostly from the Democrats. This was the first time since 1932 that the Republicans had held the Senate, recovering from a low of 16 seats following the 1936 Senate elections.
The 1942 United States Senate elections were held November 3, 1942, midway through Franklin D. Roosevelt's third term as president. The 32 seats of Class 2 were contested in regular elections, and two special elections were held to fill vacancies.
The 1938 United States Senate elections occurred in the middle of Franklin D. Roosevelt's second term. The 32 seats of Class 3 were contested in regular elections, and special elections were held to fill vacancies. The Republicans gained eight seats from the Democrats, though this occurred after multiple Democratic gains since the 1932 election, leading to the Democrats retaining a commanding lead over the Republicans with more than two-thirds of the legislative chamber.
The 1936 United States Senate elections coincided with the reelection of President Franklin D. Roosevelt. The 32 seats of Class 2 were contested in regular elections, and special elections were held to fill vacancies. The Great Depression continued and voters backed progressive candidates favoring Roosevelt's New Deal in races across the country. The Democrats gained 5 net seats during the election, and in combination with Democratic and Farmer–Labor interim appointments and the defection of George W. Norris from the Republican Party to become independent, the Republicans were reduced to 16 seats. Democrats gained a further two seats due to mid-term vacancies. The Democrats' 77 seats and their 62-seat majority remain their largest in history.
The 1932 United States Senate elections coincided with Democrat Franklin D. Roosevelt's landslide victory over incumbent Herbert Hoover in the presidential election. The 32 seats of Class 3 were contested in regular elections, and special elections were held to fill vacancies.
The 1930 United States Senate elections occurred in the middle of Republican President Herbert Hoover's term. The 32 seats of Class 2 were contested in regular elections, and special elections were held to fill vacancies. With the Great Depression beginning to take hold, Republican incumbents became unpopular, and Democrats picked up a net of eight seats, erasing the Republican gains from the previous election cycle, however, Republicans retained control of the chamber. This was the first of four consecutive Senate elections during the Depression in which Democrats made enormous gains, achieving a cumulative pick-up of 34 seats.
The 1928 United States Senate elections were elections that coincided with the presidential election of Republican Herbert Hoover. The 32 seats of Class 1 were contested in regular elections, and special elections were held to fill vacancies. The strong economy helped the Republicans to gain seven seats from the Democrats.
The 1914 United States Senate elections, with the ratification of the 17th Amendment in 1913, was the first time that all seats up for election were popularly elected instead of chosen by their state legislatures. And thus it became the first time that they were generally scheduled on Election Day to coincide with the U.S. House elections. The 32 seats of Class 3 were contested in regular elections in 1914. Special elections were also held to fill vacancies. These elections occurred in the middle of Democratic President Woodrow Wilson's first term.
The 1932 United States Senate election in North Carolina was held on November 8, 1932. Interim Democratic Senator Cameron A. Morrison ran for election to a full term, but was defeated in the Democratic primary by Robert Rice Reynolds. Reynolds defeated Republican Jacob F. Newell in the general election.
Two United States Senate elections in Connecticut were held on November 5, 1946, to determine the next United States Senator from Connecticut. One election determined who would complete the remainder of deceased Senator Francis T. Maloney's term and the other was for the regularly-scheduled term from 1947 to 1953.
The 1946 United States Senate elections in Ohio was held on November 5, 1946, alongside a concurrent special election to the same seat.
The 1928 United States Senate special election in Ohio was held on November 6, 1928 to elect a successor to Frank B. Willis, who died in office in March 1928. Republican U.S. Representative Theodore E. Burton, who previously held this seat from 1909 to 1915, won the open race to succeed him.
The 1952 United States Senate election in Michigan was held on November 4, 1952 alongside a special election to the same seat.
The 1944 United States Senate special election in New Jersey was held on November 7, 1944.
The 1926 United States Senate special election in Indiana was held on November 2, 1926, to complete the unexpired term of Senator Samuel M. Ralston, who died on October 14, 1925. Interim Republican Senator Arthur Raymond Robinson, who had been appointed to fill the seat, was re-elected to finish the term over Democrat Evans Woollen.
The 1940 United States Senate election in Michigan was held on November 5, 1940.
The 1946 United States Senate election in Michigan was held on November 5, 1946.
