The Twentieth Amendment to the Constitution directs that a new Congress convene at noon on January 3 in each odd-numbered year, unless the preceding Congress has by law designated a different day for the new Congress's convening. On November 20, 2014, the 113 th Congress completed action on H.J.Res. 129 , setting the convening date for the 114 th Congress as January 6, 2015. The joint resolution was signed into law by President Obama on December 4 ( P.L. 113-201 ). Congressional leaders planned that the 115 th Congress would convene January 3, 2017, and that the 116 th Congress would convene January 3, 2019, obviating the need for a law to set the date. In recent years, it has been the exception rather than the rule for a new Congress to begin on January 3. Nine of the past 12 Congresses began on a date other than January 3-- 104 th Congress (January 4, 1995), 105 th Congress (January 7, 1997), 106 th Congress (January 6, 1999), 108 th Congress (January 7, 2003), 109 th Congress (January 4, 2005), 110 th Congress (January 4, 2007), 111 th Congress (January 6, 2009), 112 th Congress (January 5, 2011), and 114 th Congress (January 6, 2015). The 107 th , 113 th , and 115 th Congresses were the only 3 of these 12 to begin on January 3, convening January 3, 2001; January 3, 2013; and January 3, 2017, respectively. The Vice President, named by the Constitution as President of the Senate, presides when the Senate first convenes; the Senate chaplain offers a prayer and the Vice President leads the Senate in the Pledge of Allegiance. The Vice President then announces the receipt of the certificates and credentials of election of Senators who were newly elected or reelected in the most recent general election, and of certificates of appointment for Senators newly appointed to fill a vacancy. The reading of these documents is waived by unanimous consent, and they are printed in full in the Congressional Record . The first order of business in a new Senate is the swearing-in of Senators elected or reelected in the most recent general election and of newly appointed Senators. On occasion in recent years, the majority leader or the majority and minority leaders might first be recognized for brief remarks. If there is a contested or undecided Senate election, the leadership might provide a status report and plan for its resolution, before or after Senators are sworn in. After the Vice President lays the certificates of election and appointment before the Senate and states that their reading will be waived if there is no objection, he calls those Senators to the front of the chamber, generally in alphabetical order in groups of four, to take the oath and to also "subscribe to the oath" in the official oath book. Each Senator may be accompanied by the other Senator from his or her state, the Senator he or she is replacing, or a former Senator. The oath, which is the same for Representatives and executive and judicial appointees, is as follows: I do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God. An oath is mandated by Article VI of the Constitution; its text is set by statute (5 U.S.C. 3331). When Senators take the oath, they raise their right hand to swear or affirm, repeating after the Vice President. Many Senators hold a family Bible or another item, and some hold nothing. There is no requirement that a Bible or anything else be used when the oath is taken. When the Vice President (or another individual of a Senator's choosing) and individual Senators subsequently reenact the swearing-ins in the Old Senate Chamber with the Senator's family, each Senator might hold a Bible, another item, or nothing in his or her left hand. Although photography is not permitted on the Senate floor, photographers are present for the ceremonial swearing-in. Individuals might also record a ceremonial swearing-in. After the Senators have been sworn in in the Senate chamber, the Vice President recognizes the majority leader, who notes the absence of a quorum. The Vice President directs the Senate clerk to call the roll, and all Senators are normally present to respond, fulfilling the constitutional requirement that a quorum be present to conduct business. The majority leader offers simple resolutions that the President ( S.Res. 1 , 115 th Congress) and the House ( S.Res. 2 , 115 th Congress) be formally notified that a quorum of the Senate is assembled and ready to proceed to business. Subsequently, pursuant to the resolution providing for notification of the President, the House and Senate leadership telephone the President with the news that a quorum of each house of Congress has assembled and is prepared to begin its work. As provided by the Constitution, the President pro tempore is chosen by the Senate to preside during the absence of the Vice President. Referred to as the President pro tem, this majority-party Senator usually has his party's longest continuous Senate service. When there is a change in party control of the Senate, or when a vacancy in the office of President pro tempore occurs, a new President pro tempore is elected by simple resolution and then escorted to the front of the chamber to be sworn in by the Vice President. Afterwards, the Senate adopts simple resolutions to notify the House and the President of the election of the President pro tempore. Any changes in Senate party leadership take place in the respective party conference meetings prior to opening day or, if there is a vacancy, at another time. No floor votes are needed to ratify these changes. Since the Senate is a continuing body, its officers--the secretary of the Senate, sergeant at arms and doorkeeper, chaplain, and majority and minority party secretaries--do not need to be reelected on the opening day of a new Congress. However, when there is a change in party control or a vacancy at the beginning of a Congress, any new officers are approved by the full Senate. The Senate filled a vacancy at the beginning of the 112 th Congress in electing a new secretary for the (Democratic) majority. (Party secretaries are approved by their party conferences and then elected by the Senate.) In addition, since the Senate's legal counsel and deputy legal counsel are typically appointed by the President pro tempore for the duration of only two Congresses, they are appointed or reappointed every four years and simple resolutions adopted effecting the appointments. When party control of the Senate switched with its convening in 2015, the Senate elected a new secretary and sergeant at arms, elected the majority and minority secretaries (since their roles had changed), and, as already indicated, effected the appointments of the legal counsel and deputy legal counsel for the 114 th and 115 th Congresses. The Senate also adopted simple resolutions to notify the President and the House of the election of the secretary and sergeant at arms. The Senate establishes its daily hour of meeting by a simple resolution, which must be renewed each Congress. This resolution is usually offered by the majority leader. Other organizational business is taken up on the Senate floor on the first day. At the beginning of the 115 th Congress, as in preceding Congresses, the Senate adopted en bloc by unanimous consent 11 standing orders for the duration of the current Congress. These standing orders addressed-- meetings of the Select Committee on Ethics; limiting roll-call votes to 15 minutes; authorizing Senators to present reports at the desk; allowing 10 additional minutes daily to speak for each party leader (so-called leader time); forgoing the printing of conference reports and joint explanatory statements when they are printed as House reports; allowing the Appropriations Committee to file reports during an adjournment or recess of the Senate; authorizing the secretary of the Senate to make technical and clerical corrections to engrossments of Senate-passed bills, resolutions, and amendments; during an adjournment or recess of the Senate, authorizing the secretary of the Senate to receive presidential messages and, except for House legislation, House messages, and authorizing the President pro tempore to sign enrollments; allowing Senators to designate two staff members for floor access during the Senate's consideration of specific matters; allowing treaties and nominations to be referred when received; and permitting Senators to introduce bills and resolutions by taking them to the desk. Article I, Section 2 of the Constitution provides for a system of staggered six-year terms for Senators, one-third of their terms expiring at the conclusion of each Congress. The Senate has interpreted the constitutional arrangement to mean that it is a continuing body, since a quorum is always sworn, and that it therefore does not have to organize itself with each new Congress, as does the House of Representatives. One consequence, among others, of this interpretation is that the Senate does not adopt or re-adopt its rules when a new Congress convenes, the interpretation meaning that the rules continue in effect from one Congress to the next. Other first-day activities might occur as a consequence of specific circumstances. For example, following a presidential election, the Senate must adopt a concurrent resolution to meet in joint session with the House to count the electoral votes for the President and Vice President, continue the Joint Congressional Committee on Inaugural Ceremonies, and permit use of the Capitol for inaugural activities. On the first day of the 106 th Congress, there were several announcements and a discussion related to the pending impeachment trial of President Bill Clinton. The Republican and Democratic leaders might address the Senate, possibly describing highlights of the legislative schedule ahead or discussing other pertinent issues. Other Senators might be recognized to speak after the Senate has completed its proceedings involving the oath of office and the consideration of resolutions and unanimous consent requests. Sometimes on the first day, the Senate might also adopt a concurrent resolution providing for a January adjournment or for the joint session at which Congress will receive the President's State of the Union address. The Senate might also by unanimous consent set an initial date other than the convening day on which bills and joint resolutions may be introduced, and might also agree to begin consideration of legislation at a later date. In the 112 th Congress, one of the first matters the Senate took up after Senators were sworn was a simple resolution ( S.Res. 4 ) honoring Senator Barbara Mikulski "for becoming the longest-serving female Senator in history." The Senate also agreed to S.Con.Res. 2 , allowing the Capitol Rotunda to be used for a commemorative ceremony marking the 50 th anniversary of the inaugural address of President John F. Kennedy. Finally, Majority Leader Harry Reid and Minority Leader Mitch McConnell agreed that the Senate should establish a working group under the chair and ranking minority member of the Senate Rules Committee to streamline the confirmation process for nominees to lower-level executive branch positions. The Senate has traditionally reserved bill numbers S. 1 through S. 10 for the majority party and S. 11 through S. 20 for the minority party. A Senator with his or her leadership's approval might introduce a bill at any time during the two-year Congress using one of the numbers reserved for the Senator's party. Senator John Hoeven, with Majority Leader Mitch McConnell's support, introduced S. 1 on the first day of the 114 th Congress (see the next paragraph). Then-Majority Leader Harry Reid and his cosponsors used all 10 bill numbers on the first day of the 111 th Congress, when President Obama was soon to be inaugurated and Democrats organized both houses of Congress. The bills addressed party priorities for economic, energy, health, social, and national security policies. In the 114 th Congress, the majority leader immediately began proceedings to introduce and bring to the floor S. 1 , to approve the Keystone XL pipeline. The majority leader obtained unanimous consent to allow bills and resolutions to be introduced until 4:00 p.m., notwithstanding the Senate's adjournment before that time on its day of convening. He also sought, but did not receive, unanimous consent to make initial majority and minority assignments to the Energy and Natural Resources Committee. He began the process under Senate Rule XIV to place S. 1 directly on the Senate Calendar. Separately, the majority leader with all other 99 Senators as cosponsors agreed to a resolution ( S.Res. 19 ) expressing the sorrow of the Senate upon the death of former Senator Edward W. Brooke III, who in addition to his Senate service had been recognized for his achievements with both the Presidential Medal of Freedom and the Congressional Gold Medal. After the Senate has completed its organizational proceedings, it may turn to other activities it has agreed to undertake, such as the introduction and reference of legislation, speeches, and appointments. In addition, following the sine die adjournment of the preceding Congress through the convening of the new Congress, the secretary of the Senate will have received, in the Senate's behalf, messages from the House of Representatives, the President, and executive departments and agencies. The Senate also receives new messages, such as from the House on its convening and election of the Speaker and its officers. On the first day of a new Congress, messages will be disposed of, typically by reference to the relevant committee. Certain administrative notices might also appear in the opening-day Congressional Record . Certain records might also appear in the opening-day Congressional Record . Negotiations between parties over committee sizes and ratios and separate committee assignment processes begin prior to the convening of a new Congress, and mostly within the party groups--the Democratic and Republican Conferences. The only action visible on the chamber floor is the subsequent adoption of simple resolutions assigning Senators from each party to committees agreed upon by the respective party conference. The adoption of both parties' resolutions is routine. Committee assignment resolutions are not normally considered on the opening day of a new Congress, but later in January. On the opening day of the 107 th Congress, an assignment resolution (S.Res.) was taken up to designate committee chairs, pending an agreement on the organization of the Senate under the special circumstance of 50 Democratic and 50 Republican Senators. Committee funding resolutions (S.Res.) are also considered later in February or early March. In years in which a new President will be inaugurated, Senate committees begin hearings on designated Cabinet secretaries, pending the formal submission of nominations once the President-elect has been inaugurated.

Summary:
The Constitution mandates that Congress convene at noon on January 3, unless the preceding Congress by law designated a different day. P.L. 113-201 set January 6, 2015, as the convening date of the 114th Congress. The 115th Congress convened on January 3, 2017. Congressional leaders announced the 116th Congress would convene January 3, 2019. The Senate follows a well-established routine on the opening day of a new Congress. The proceedings include swearing in Senators elected or reelected in the most recent general election (approximately one-third of the Senate) or newly appointed to the convening Senate; establishing the presence of a quorum; adopting administrative resolutions; adopting standing orders for the new Congress; agreeing by unanimous consent to a date, other than the convening date, on which bills and joint resolutions may begin to be introduced; and electing a new President pro tempore and one or more Senate officers if there is a vacancy or a change in party control. The majority and minority leaders usually make welcoming remarks during the day's proceedings. If an election to a Senate seat is undecided or subject to consideration by the Senate, the majority leader and other Senators might address the Senate's posture on that election. Other first-day activities may occur as a consequence of specific circumstances, such as providing for a joint session with the House to count electoral votes after a presidential election. After Senators are sworn or after organizational proceedings are completed, the Senate may turn to legislative or executive business or other activities. Following their official swearing-in on the Senate floor, newly sworn Senators gather with their families in the Old Senate Chamber for ceremonial swearing-ins with the Vice President or another official of their choosing. The ceremonial swearing-ins may be photographed and recorded. Negotiations between parties over committee sizes and ratios, parties' action on committee assignments, and parties' decisions on party leadership changes and organization may begin during the early organization meetings for the new Senate, which occur in November and December following a general election. The committee assignment process may continue after the beginning days of a new Congress. At some time, usually other than opening day, the Senate adopts committee assignment resolutions. Any changes in Senate party leadership take place in respective party conference meetings. There are no floor votes to ratify party leadership changes. For an explanation of proceedings occurring on the first day in the House of Representatives, see the companion report: CRS Report RL30725, The First Day of a New Congress: A Guide to Proceedings on the House Floor.