A special election is an election held to fill a seat that becomes vacant between the regular elections. Congressional seats normally come up on a fixed schedule, but a seat can open early if a member resigns, dies, or leaves office for another job. When that happens, the seat does not stay empty until the next general election. It is filled through a separate process that depends on the chamber and the state.
When special elections happen
A vacancy can open for several reasons. A member might resign, take a different office, be expelled, or pass away. Because each district and each state is supposed to have full representation, the seat needs to be filled. House seats and Senate seats are handled differently.
How House vacancies are filled
When a U.S. House seat becomes vacant, the Constitution requires a special election in that district. The state’s governor calls the election, and voters in the district choose a new Representative to serve the rest of the term. A House seat cannot be filled by appointment, so a special election is the only way to fill it. The winner serves until the next regular election for that seat.
How Senate vacancies are filled
Senate vacancies work differently and depend on state law. In most states, the governor can appoint a temporary senator to serve until a special election or the next regular election. Some states require the appointee to be from the same party as the senator who left. A few states fill the seat by special election without an appointment. So a Senate vacancy may be filled quickly by appointment, while a House vacancy waits for voters.
How long the new member serves
A member elected or appointed in a vacancy serves the remainder of the original term, not a fresh full term. For House seats that means serving until the next even-numbered-year election. For Senate seats it depends on when the vacancy falls within the six-year term. For more on the regular schedule, see How Long Is a Congressional Term, and When Are Elections?
How a special election is run
A special election follows the same basic steps as a regular election, compressed into a shorter timeline. The state sets the date, candidates qualify for the ballot, and in many cases the parties hold a primary or nominating contest first. A vacancy can also open if a member is appointed or elected to another office, such as a governorship or a Cabinet post. Turnout in special elections is often lower than in regular November elections, since they fall on off dates, so a smaller share of voters can decide the result.
Why special elections matter
A single special election can shift the balance in a closely divided House or Senate, so these races sometimes draw national attention and heavy spending even though they fill just one seat. For the district or state involved, a special election restores full representation rather than leaving the seat empty until the next general election.
Getting on a special-election ballot
The way candidates qualify for a special election varies by state. Some hold a quick party primary first, then a general election weeks later. Others put every candidate on a single ballot, with a runoff if no one wins a majority. Timelines are compressed, so filing deadlines, signature requirements, and campaign windows all move faster than in a regular election. The exact rules are set by the state holding the vote.
Turnout in special elections
Special elections usually draw fewer voters than a regular November election, because they fall on unfamiliar dates and lack the top-of-ticket races that pull people to the polls. Lower turnout can make the result harder to predict and puts a premium on which side does more to remind its voters. For that reason, even a single House special election can attract heavy national attention and spending.
Who pays and when it is held
The state or locality generally bears the cost of running a special election, which is one reason some are combined with an already-scheduled election date. A governor or state election office sets the date within the limits of state law. When a vacancy happens close to a regular election, officials may simply let the seat stay open until then rather than hold a separate vote.
What a special election does not change
A special election fills the rest of an unexpired term, nothing more. The winner serves only until the term would have ended, and the seat then returns to its normal schedule. So a House seat won in a special election is up again at the next regular election, and a Senate seat keeps its place in the six-year cycle. The special vote changes who holds the seat, not when it is next contested.
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Last updated June 18, 2026.
