United States senators are conventionally ranked by the length of their tenure in the Senate. The senator in each U.S. state with the longer time in office is known as the senior senator; the other is the junior senator.

The United States Senate consists of 100 members, two from each of the 50 states. This list includes all senators serving in the 119th United States Congress.

Seniority in the United States Senate is the value of a senator based on his/her service. There are two senators per state. The one senator that served more years is called the Senior senator. The one who served less is called the Junior senator.

This is a complete list of United States senators during the 118th United States Congress listed by seniority, from January 3, 2023, to January 3, 2025. It is a historical listing and will contain people who have not served the entire two-year Congress should anyone resign, die, or be expelled.

This is a complete list of United States senators during the 117th United States Congress listed by seniority, from January 3, 2021, to January 3, 2023. It is a historical listing and will contain people who have not served the entire two-year Congress should anyone resign, die, or be expelled.

For senators who entered the Senate on the same day, several tie-breaking procedures determine seniority. In order of precedence, these factors are: previous Senate service, service as the vice president, previous House service; service in the Cabinet, service as a state governor.

In the vice president's absence, the president pro tempore, who is traditionally the most senior member of the Senate's majority party, presides over the Senate, and more often by rule allows a junior senator to take the chair, guided by the parliamentarian.

United States senators are conventionally ranked by the length of their tenure in the Senate. The senator in each U.S. state with the longer time in office is known as the senior senator; the other is the junior senator.

The practice of ranking senators based on length of service, known as seniority, developed during the institution's first half-century. In its earliest decades, the Senate struggled to find an equitable means for distributing special status among members.

Rebecca Latimer Felton (D-Georgia), the first female member of the United States Senate, who served for a single day in 1922. One woman (Barbara Mikulski) was reelected and four women were elected to the Senate in 1992, the "Year of the Woman," Left to right: Senators Murray, Moseley Braun, Mikulski, Feinstein, and Boxer.By the 111th United States Congress …