The U.S. Senate by the Numbers

12 facts about the upper chamber of the United States Congress 

The Senate is part of the legislative branch, which has the power to make laws. Some of the chamber’s key responsibilities include approving treaties and nominations for appointed U.S. government officials, including Supreme Court justices and Cabinet leaders. The Senate was designed to give each state — no matter the size of its population — equal voting power.

2

The number of senators representing each state, giving the Senate 100 voting members.

The number of years in a senator’s term. One-third of senators are up for re-election every two years, so the chamber does not all turn over at once. 

51 

The number of years served by the longest-tenured U.S. senator, Robert Byrd of West Virginia. Before joining the Senate in 1959, he served six years in the House of Representatives. 

1789

The year the first Senate convened. Twenty-two senators were supposed to meet on March 4, but only eight were able to get there on time.

1913

The year the 17th Amendment was adopted, allowing voters to elect their senators directly. Prior to this, state legislatures chose senators.

51

The number of votes needed for a simple majority, the requirement for passing legislation and setting procedural rules.

67 

The number of votes needed for a two-thirds supermajority, required for overriding a presidential veto, expelling members from the Senate, proposing a constitutional amendment, approving a treaty, convicting an impeached federal official, and removing a president from office. 

25

The number of political parties that have held seats in the Senate since 1790.

1,984 

The number of senators who have served since 1790.

268 

The number of times a vice president has cast a tiebreaking vote in the Senate.

51 

The number of senators required to be present in order to conduct business.

16 

The number of standing committees that are in the Senate, including committees on agriculture, finance, and foreign relations.


Learn more about:
The Senate’s role (Truman Library)
Senate powers and procedures (U.S. Senate
Congressional committees (U.S. Congress)
The 17th Amendment (National Archives)
Historical facts and milestones (U.S. Senate)

Find more resources here.

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