The 1990 United States Senate elections were held on Tuesday, November 6, 1990, with the 33 seats of Class 2 contested in regular elections. Special elections were also held to fill vacancies. The Democratic Party increased its majority with a net gain of one seat from the Republican Party. The election cycle took place in the middle of President George H. W. Bush's term, and, as with most other midterm elections, the party not holding the presidency gained seats in Congress.
The 1984 United States Senate elections were held on November 6, with the 33 seats of Class 2 contested in regular elections. They coincided with the landslide re-election of President Ronald Reagan in the presidential election. In spite of the lopsided presidential race, Reagan's Republican Party suffered a net loss of two Senate seats to the Democrats, although it retained control of the Senate with a reduced 53–47 majority. Democrats defeated incumbents in Illinois and Iowa, and won an open seat in Tennessee, while Republicans defeated an incumbent in Kentucky.
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.
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 1976 United States Senate elections was an election for the United States Senate. Held on November 2, the 33 seats of Class 1 were contested in regular elections. They coincided with Democrat Jimmy Carter's presidential election and the United States Bicentennial celebration. Although almost half of the seats decided in this election changed parties, Carter's narrow victory did not provide coattails for the Democratic Party. Each party flipped seven Senate seats, although, one of the seats flipped by Democrats was previously held by a Conservative.
The 1972 United States Senate elections were held on November 7, with the 33 seats of Class 2 contested in regular elections. They coincided with the landslide re-election of Republican President Richard Nixon. Despite Nixon's landslide victory, Democrats increased their majority by two seats. The Democrats picked up open seats in Kentucky and South Dakota, and defeated four incumbent senators: Gordon Allott of Colorado, J. Caleb Boggs of Delaware, Jack Miller of Iowa, and Margaret Chase Smith of Maine. The Republicans picked up open seats in New Mexico, North Carolina, and Oklahoma, and defeated one incumbent, William B. Spong Jr. of Virginia.
The 1970 United States Senate elections was an election for the United States Senate. It took place on November 3, with the 33 seats of Class 1 contested in regular elections. Special elections were also held to fill vacancies. These races occurred in the middle of Richard Nixon's first term as president. The Democrats lost a net of three seats, while the Republicans and the Conservative Party of New York picked up one net seat each, and former Democrat Harry F. Byrd Jr. was re-elected as an independent.
The 1968 United States Senate elections were elections for the United States Senate. Held on November 5, the 34 seats of Class 3 were contested in regular elections. They coincided with the presidential election of the same year. The Republicans picked up five net seats in the Senate. This saw Republicans win a Senate seat in Florida for the first time since Reconstruction.
The 1964 United States Senate elections were held on November 3. The 33 seats of Class 1 were contested in regular elections. Special elections were also held to fill vacancies. They coincided with the election of President Lyndon B. Johnson by an overwhelming majority, to a full term. His Democratic Party picked up a net two seats from the Republicans. As of 2023, this was the last time either party has had a two-thirds majority in the Senate, which allowed the Senate Democrats to override a veto, propose constitutional amendments, or convict and expel certain officials without any votes from Senate Republicans. However, internal divisions would have prevented the Democrats from having done so. The Senate election cycle coincided with Democratic gains in the House in the same year.
The 1960 United States Senate elections coincided with the election of John F. Kennedy as president on November 8, 1960. The 33 seats of Class 2 were contested in regular elections. A special election was also held on June 28, 1960, for a mid-term vacancy in North Dakota where Democrats flipped a seat to expand their majority to 66–34. As Majority Leader Lyndon Johnson was elected Vice President, Mike Mansfield became the new majority leader.
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 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 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 1978 United States Senate election in Minnesota was held on November 7, 1978. Incumbent Democratic U.S. Senator Wendell Anderson was defeated by Republican challenger Rudy Boschwitz.
The 1952 United States Senate election in Minnesota took place on November 4, 1952. Incumbent Republican Edward John Thye defeated Democratic challenger Bill Carlson to win a second term.
The 1946 United States Senate election in Minnesota took place on November 5, 1946. It was the first election to either of Minnesota's seats in the United States Senate held since the Minnesota Democratic Party and the Farmer-Labor Party of Minnesota merged in 1944, to form the Minnesota Democratic-Farmer-Labor Party. Incumbent U.S. Senator Henrik Shipstead was defeated in the Republican primary by Governor Edward John Thye, who went on to defeat DFL challenger Theodore Jorgenson in the general election.
The 1964 United States Senate election in Minnesota took place on November 3, 1964. Incumbent Democratic U.S. Senator Eugene McCarthy defeated Republican challenger Wheelock Whitney Jr., to win a second term.
The 1970 United States Senate election in Minnesota took place on November 3, 1970. Incumbent Democratic U.S. Senator Eugene McCarthy opted not to seek reelection. Former Democratic U.S. Senator, former Vice President and 1968 presidential nominee Hubert Humphrey defeated Republican U.S. Representative Clark MacGregor.
The 1972 United States Senate election in Arkansas took place on November 7, 1972. Incumbent U.S. Senator John L. McClellan was re-elected to a sixth term in office, defeating U.S. Representative David Pryor in a hotly contested primary. In the general election, McClellan easily defeated Republican physician Wayne Babbitt. This was McClellan's final campaign; he died in his sleep in 1977. Pryor was elected Governor of Arkansas in 1974 and won the race to succeed McClellan in 1978.
The 1958 United States Senate election in New Jersey was held on November 4, 1958.
