Every two years, Americans vote for members of the U.S. Congress. In some of those years, the presidency is on the ballot too. In the years between presidential elections, congressional elections are commonly known as midterm elections.
This guide explains what midterm elections are, which federal offices are elected, and how elections for the House of Representatives and Senate work.
What Are Midterm Elections?
Midterm elections are congressional elections held halfway through a president’s four-year term.
Every voting seat in the U.S. House of Representatives is normally up for election during a midterm, along with about one-third of the Senate. The president and vice president are not elected during a midterm election.
Voters may also choose governors, state legislators, local officials, judges, or decide ballot measures during the same election cycle. What appears on a ballot varies by state and locality.
The 2026 midterm Election Day is Tuesday, November 3, 2026.
Last verified: September 2026.
Why Are They Called Midterm Elections?
The name describes where these elections fall within a presidential term.
A president serves a four-year term. Members of the House serve two-year terms, so House elections take place every two years. This means one congressional election occurs at approximately the midpoint of each presidential term.
The Constitution requires House members to be chosen every second year. The Senate follows a different system: senators serve six-year terms, but their seats are divided into three classes so that approximately one-third of the Senate is normally elected every two years.
As a result, congressional elections occur in both presidential-election years and midterm years.
What Is Elected During the Midterms?
At the federal level, midterm elections normally include:
- All 435 voting seats in the U.S. House of Representatives
- One of the Senate’s three classes, representing about one-third of Senate seats
- Special congressional elections, when applicable, to fill certain vacancies
The House also includes non-voting delegates representing the District of Columbia, the U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands, as well as a resident commissioner from Puerto Rico. These positions are not part of the House’s 435 voting membership.
The president and vice president are not normally elected during midterms because presidential elections occur every four years.
Supreme Court justices are also not elected by voters. They are nominated by the president and appointed with the advice and consent of the Senate.
When Are Midterm Elections Held?
Federal law establishes the regular congressional election date as the Tuesday after the first Monday in November in every even-numbered year.
Regular House and Senate elections therefore take place on the same federal Election Day.
For the 2026 midterms, Election Day falls on November 3, 2026.
Under the 20th Amendment, congressional terms begin at noon on January 3 following the election.
States play a major role in administering congressional elections. Article I of the Constitution gives states authority over the times, places, and manner of congressional elections while also giving Congress authority to make or alter many of those regulations.
Primary elections and other contests leading up to the general election follow additional federal and state rules and schedules.
How House Elections Work
435 Voting Members
The House of Representatives has 435 voting members.
Representatives serve two-year terms, which means all 435 voting seats are normally contested during every regular congressional election cycle — both presidential-election years and midterm years.
Congressional Districts
Representatives are generally elected from individual congressional districts.
Federal law requires states with more than one House seat to use districts, with each district electing one representative.
States with only one House seat have a single statewide, or at-large, congressional district.
Census, Apportionment and Redistricting
Several related processes determine how House representation works.
Census: The Constitution requires a population count every ten years.
Apportionment: After the decennial census, the 435 House seats are distributed among the 50 states according to population. Every state receives at least one representative.
Redistricting: Once a state’s number of House seats is known, congressional district boundaries are drawn within the state. The specific redistricting process varies by state and is also subject to applicable federal law.
House elections: Voters in each congressional district elect the representative for that district.
Redistricting commonly occurs following the census and reapportionment process. Congressional maps can also change at other times under some circumstances. The U.S. Constitution and federal law do not generally prohibit mid-decade congressional redistricting, although other federal requirements and state laws can constrain how and when maps are redrawn.
Last reviewed: September 2026.
Qualifications for the House
The Constitution establishes three qualifications for serving as a U.S. representative:
- At least 25 years old
- A U.S. citizen for at least seven years
- An inhabitant of the state represented when elected
The Constitution requires state residency; it does not require a representative to live within the particular congressional district represented.
How Senate Elections Work
100 Senators
The Senate has 100 members — two from each state.
Unlike House representation, which is apportioned according to population, every state has the same number of senators.
Senators serve six-year terms and are elected statewide.
The Constitution originally provided for senators to be selected by state legislatures. The 17th Amendment, ratified in 1913, established direct popular election of senators.
The Three Senate Classes
The entire Senate is not elected at once.
The Constitution divides Senate seats into three classes so that approximately one-third of the Senate is normally elected every two years.
The current class arrangement contains:
- One class with 34 seats
- Two classes with 33 seats each
This staggered system means roughly two-thirds of senators remain in office when another class faces its regular election.
Each Senate seat normally comes up for election once every six years.
Qualifications for the Senate
The Constitution establishes three qualifications for senators:
- At least 30 years old
- A U.S. citizen for at least nine years
- An inhabitant of the state represented when elected
House vs. Senate Elections
| House of Representatives | Senate | |
|---|---|---|
| Voting members | 435 | 100 |
| Term | 2 years | 6 years |
| Constituency | Congressional district, or statewide in a one-seat state | Entire state |
| Seats normally up each cycle | All 435 | About one-third |
| Minimum age | 25 | 30 |
| Citizenship requirement | At least 7 years | At least 9 years |
| Residency requirement | Inhabitant of the state represented | Inhabitant of the state represented |
| Regular election cycle | Every 2 years | Each seat every 6 years, staggered among three classes |
What Else Can Appear on a Midterm Ballot?
Congressional races may be only part of what voters see during a midterm election.
Depending on the state and locality, ballots may also include elections for:
- Governors and other state executive offices
- State legislators
- County and municipal officials
- Judges
- Other state or local offices
- Ballot measures or initiatives
Not every state elects the same offices at the same time. State and local election calendars vary, so voters should use their official state or local election authority to determine what will appear on their ballot.
What Happens When a Congressional Seat Becomes Vacant?
The House and Senate handle vacancies differently.
House Vacancies
The Constitution requires a state’s executive authority to issue a writ of election when a House seat becomes vacant.
In practical terms, House vacancies are filled through elections rather than temporary appointments. The timing and procedures for these special elections generally depend on applicable state and federal law.
Senate Vacancies
The 17th Amendment also provides for elections to fill Senate vacancies, but it permits a state’s legislature to authorize the state’s executive to make a temporary appointment until voters elect a successor.
Because state laws differ, the exact process and timing for filling a Senate vacancy can vary from state to state.
How Midterms Fit Into the U.S. Election Cycle
Congressional elections occur every two years.
The cycle alternates between:
Presidential-election years: Voters elect the president and vice president while also electing all 435 voting House members and the Senate class scheduled for that cycle.
Midterm years: No regular presidential election occurs. Voters elect all 435 voting House members and another Senate class.
This pattern continues every two years, with the three Senate classes rotating through their six-year terms.
For a detailed explanation of how the president is chosen, see How U.S. Presidential Elections Work: A Step-by-Step Guide.
Key Takeaway
Midterm elections are congressional elections held halfway through a president’s four-year term.
All 435 voting House seats are normally contested because representatives serve two-year terms. Senators serve six-year terms, with the Senate divided into three classes so that approximately one-third of its seats are normally contested every two years.
House members represent congressional districts, while senators represent entire states. At the same time, voters may encounter many state and local contests depending on where they live.
Together, these staggered election cycles allow voters to choose members of Congress every two years, whether or not a presidential election is taking place.
Sources
- U.S. Constitution, Article I — Constitution Annotated, Congress.gov
- U.S. Constitution, 17th Amendment — Constitution Annotated, Congress.gov
- U.S. Constitution, 20th Amendment — Constitution Annotated, Congress.gov
- U.S. Code, Title 2 — congressional election, apportionment and districting provisions
- U.S. Senate — Senators Receive Class Assignments
- U.S. Senate — Electing and Appointing Senators
- U.S. Census Bureau — Congressional Apportionment
- USAGov — Congressional Elections and Midterm Elections
- USAGov — State and Local Elections
- Congressional Research Service — Mid-Decade Congressional Redistricting: Key Issues
Election-related information last reviewed September 2026. The American Elections is an independent educational resource and is not affiliated with any campaign, political party, or election authority.
