The 100 seats in the United States Senate are divided into 3 classes to determine which seats will be up for election in any 2-year cycle, with only 1 class being up for election at a time. With senators being elected to fixed terms of 6 years, the classes allow about a third of the seats to be up for election in any presidential or midterm election year instead of having all 100 be up for election at the same time every six years. The seats are also divided in a way that any given state's 2 senators are in different classes so that each seat's term ends in different years. Class 1 and class 2 consist of 33 seats each, while class 3 consists of 34 seats. Elections for class 1 seats are scheduled to take place in 2024, class 2 in 2026, and the elections for class 3 seats in 2028.
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 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 1924 United States Senate elections were elections for the United States Senate which coincided with the election of Republican President Calvin Coolidge to a full term. The 32 seats of Class 2 were contested in regular elections, and special elections were held to fill vacancies. The strong economy and Coolidge's popularity helped Republican candidates increase their majority by three. Republicans would gain a further two seats through mid-term vacancies bringing their seat share to 56-39-1.
The 1802–03 United States House of Representatives elections were held on various dates in various states between April 26, 1802 and December 14, 1803. Each state set its own date for its elections to the House of Representatives, either before or after the first session of the 8th United States Congress convened on October 17, 1803. They occurred during President Thomas Jefferson's first term in office.
The 1803 United States Senate election in New York was held on February 1, 1803, by the New York State Legislature to elect a U.S. Senator to represent the State of New York in the United States Senate.
The first 1804 United States Senate special election in New York was held on February 3, 1804, by the New York State Legislature to elect two United States Senators to represent the State of New York in the United States Senate.
The 1804–05 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1804 and 1805, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 2.
The 1806–07 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1806 and 1807, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 3.
The 1808–09 United States Senate elections were held on various dates in various states, coinciding with the 1808 presidential election. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1808 and 1809, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 1.
The 1812–13 United States Senate elections were held on various dates in various states, coinciding with President James Madison's re-election. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1812 and 1813, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 3.
The 1802–03 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1802 and 1803, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 1.
The 1792–93 United States Senate elections were held on various dates in various states, coinciding with President George Washington's unanimous re-election. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1792 and 1793, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the ten senators in Class 2.
The 1802 United States House of Representatives elections in New York were held from April 27 to 29, 1802, to elect 17 U.S. Representatives to represent the State of New York in the United States House of Representatives of the 8th United States Congress.
The 1804 United States House of Representatives elections in New York were held from April 24 to 26, 1804, to elect 17 U.S. Representatives to represent the State of New York in the United States House of Representatives of the 9th United States Congress. At the same time, a vacancy was filled in the 8th United States Congress.
The 1803 United States Senate election in Massachusetts was held in February 1803.
A special election was held in Georgia's at-large congressional district on October 3, 1803 to fill a vacancy caused by the resignation, before the start of the 8th Congress, of John Milledge (DR), who had been elected Governor of Georgia.
A special election was held in Georgia's 2nd congressional district in 1827 to fill a vacancy caused by the resignation of John Forsyth (J).
A special election filled the remainder of the term in the United States House of Representatives for Georgia's 5th congressional district in the 116th United States Congress. Incumbent representative John Lewis, who was diagnosed with pancreatic cancer in December 2019, died on July 17, 2020, during his 17th term.
