List of United States senators in the 113th Congress
This is a complete list of members of the United States Senate during the 113th United States Congress listed by seniority, from January 3, 2013, to January 3, 2015. 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. Order of service is based on the commencement of the senator's first term. Behind this is former service as a senator (only giving the senator seniority within his or her new incoming class), service as vice  president, a House member, a cabinet secretary, or a governor of a state. The final factor is the population of the senator's state. Senators who were sworn in during the middle of the two-year Congress (up until the last senator who was not sworn in early after winning the November 2014 election) are listed at the end of the list with no number. In this Congress, Tom Harkin (Iowa) was the most senior junior senator. Brian Schatz (Hawaii) was the most junior senior senator until February 1, 2013, when John Kerry's resignation to become Secretary of State  made Elizabeth Warren (Massachusetts) the most junior senior Senator. The 113th Congress was the first Congress since the 103rd Congress (1993–95) without a senator who had served for at least 40 years. The most senior senator, Patrick Leahy, did not reach the 40-year mark until January 3, 2015. From November 7, 1996, when Strom Thurmond reached the 40-year mark during the 104th Congress, until Daniel Inouye died on December 17, 2012, there was always at least one senator who had served for 40 years.