Classes of United States senators facts for kids

The United States Senate has 100 members, called senators. These 100 seats are divided into three groups, or "classes," to decide when they will be up for election. Senators serve for six years. Instead of all 100 senators being elected at the same time every six years, the class system means that about one-third of the Senate seats are up for election every two years. This happens during either a presidential election year or a midterm election year.

The two senators from any single state are always in different classes. This means their terms end in different years. Class 1 and Class 2 each have 33 seats. Class 3 has 34 seats. For example, elections for Class 1 seats are planned for 2024, Class 2 in 2026, and Class 3 in 2028.

The idea for these three classes comes from Article I, Section 3, Clause 2 of the U.S. Constitution. The very first Senate, in May 1789, decided which senators belonged to which class by drawing lots (like a random draw). When new states joined the country later, their two Senate seats were also assigned to two different classes by a random draw. This helped keep the three classes as close to the same number of senators as possible.

The class system only applies to regular elections. If a senator leaves office early (for example, by resigning or dying), a special election might be held to fill that spot. This special election can happen in any year, no matter what class the seat belongs to. Also, whether a senator is called "junior" or "senior" isn't about their class. It's about how long they have served in the Senate.

History of Senate Classes

How the Constitution Created Classes

The U. S. Constitution says that senators serve for six years. It also planned for their elections to be staggered. This means that about one-third of the Senate is up for election every two years. This system helps keep the Senate stable. It encourages senators to think carefully about new laws over time. It also prevents all 100 senators from changing at once every six years. At the same time, having elections every two years means people can vote more often.

Article I, Section 3 of the U.S. Constitution explains the three classes:

Immediately after they shall be assembled in Consequence of the first Election, they shall be divided as equally as may be into three Classes. The Seats of the Senators of the first Class shall be vacated at the Expiration of the second Year, of the second Class at the Expiration of the fourth Year, and of the third Class at the Expiration of the sixth Year, so that one third may be chosen every second Year.

The first Senate met in May 1789. They decided how to divide the senators into classes. On May 14, 1789, they agreed to divide the members into three classes. They used a random draw to decide which class would have its terms end first, second, and third. This made sure that some senators would serve for two years, some for four, and some for six, right from the start.

Adding New States

When a new state joins the United States, its two senators are placed into two different classes. This is done to keep the number of senators in each class as even as possible. A random draw decides which new senator goes into which of the chosen classes. This means one of the new state's first senators will serve a longer term (up to six years), and the other will serve a shorter term (two or four years less).

For example, when New York joined in 1789, its senators, Philip Schuyler and Rufus King, drew lots. Schuyler ended up in Class 1 (term ending in 1791), and King in Class 3 (term ending in 1795). This helped balance the classes. When Hawaii became a state in 1959, its first senators, Hiram Fong and Oren E. Long, also drew lots to decide their classes.

If a 51st state were to join, its senators would likely be placed in Class 1 and Class 2. This would make all three classes have 34 senators each.

Class 1

Map shows the classes in each U.S. State:
     Classes 1 and 2     Classes 1 and 3     Classes 2 and 3

Class 1 includes:

• The 33 current senators whose seats will be up for re-election in November 2024. Their terms end on January 3, 2025.
• All past senators whose terms ended in years like 1791, 1797, 1803, and so on, up to 2019.

States with a Class 1 senator include: Arizona, California, Connecticut, Delaware, Florida, Hawaii, Indiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Jersey, New Mexico, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming.

Class 2

Class 2 includes:

• The 33 current senators whose seats will be up for re-election in November 2026. Their terms end on January 3, 2027.
• All past senators whose terms ended in years like 1793, 1799, 1805, and so on, up to 2021.

States with a Class 2 senator include: Alabama, Alaska, Arkansas, Colorado, Delaware, Georgia, Idaho, Illinois, Iowa, Kansas, Kentucky, Louisiana, Maine, Massachusetts, Michigan, Minnesota, Mississippi, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, North Carolina, Oklahoma, Oregon, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Virginia, West Virginia, and Wyoming.

Class 3

Class 3 includes:

• The 34 current senators whose seats will be up for re-election in November 2028. Their terms end on January 3, 2029.
• All past senators whose terms ended in years like 1795, 1801, 1807, and so on, up to 2023.

States with a Class 3 senator include: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Missouri, Nevada, New Hampshire, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Utah, Vermont, Washington, and Wisconsin.

Senate Election Years

This table shows when each class of senators has their elections.

Senators by Class and Party

This table shows how many senators from each political party are in each class.

Senate composition by class, state & party

Class 1

Class 2

Class 3

      Democrat       Independent who caucuses with Democrats
      Republican

      Not up for election

See also

In Spanish: Clases de senadores de los Estados Unidos para niños