A session of Congress is the formal yearly period during which the House and Senate meet to pass laws, confirm appointments, and oversee the executive branch. The 20th Amendment requires Congress to convene at least once each year, beginning at noon on January 3 unless lawmakers set a different date by statute.1Legal Information Institute. U.S. Constitution – Amendment XX Each two-year Congress contains two of these sessions, one per calendar year, and the rules governing when they start, how they pause, and how they end shape almost every deadline in Washington.
Terms and Sessions: The Two-Year Structure
Each Congress lasts two years and is numbered sequentially from the first Congress that met in 1789. The 119th Congress covers 2025 and 2026. Within that window there are two sessions: the first runs through the odd-numbered year, the second through the even-numbered year. The 119th Congress opened its second session on January 5, 2026, targeting adjournment on December 18, 2026.2United States Senate. 2026 Senate Calendar
The distinction between the two sessions matters less than the distinction between one Congress and the next. Bills carry over from the first session to the second without losing their place; a measure that spent months in committee during 2025 picks up in 2026 with its number, referrals, and hearing record intact. But the hard deadline hits at the end of the two-year term. Any bill that hasn’t become law by the time the Congress adjourns for the final time is dead, and a member who wants to revive it must reintroduce it in the next Congress and start over.3Library of Congress. What Happens to a Bill That Has Not Become Law That is why so many major bills pile up in the final weeks of a Congress.
When a Session Meets
The original Constitution required Congress to meet on the first Monday in December each year.4Legal Information Institute. U.S. Constitution – Article I The 20th Amendment, ratified in 1933, moved that date to January 3 at noon, while allowing Congress to pick a different start date by law.1Legal Information Institute. U.S. Constitution – Amendment XX In practice, opening day sometimes slips a day or two to avoid weekends.
Once open, a modern session stretches across nearly the whole calendar year, but a session’s length is not the same as its number of legislative days. Since 2001, the House has averaged roughly 147 legislative days per year and the Senate around 165.5Congress.gov. Days in Session of the U.S. Congress – 119th Congress The rest of the weeks are filled with what Congress calls district work periods, scheduled breaks during which the session stays open but no floor votes occur. Members return home to meet with constituents and prepare for upcoming legislation. The session does not end just because the chamber isn’t voting.
The August Recess
The most prominent scheduled break is August. Congress formalized this through the Legislative Reorganization Act of 1970, which required both chambers to take a summer break in August during odd-numbered years and left even-numbered election years flexible. By the 1990s it had become an annual fixture regardless. It isn’t untouchable, though. The Senate shortened or canceled it entirely in 1994, 2005, and 2018, when pressing legislative business demanded it.6U.S. Senate. Give Us a (Summer) Break: Origins of the August Recess
Quorum: What It Takes to Conduct Business
For either chamber to conduct official business, a quorum must be present. The Constitution sets that threshold at a majority of each chamber’s membership.7Legal Information Institute. Quorums in Congress In the House, that is 218 of 435 members. In the Senate, 51 of 100.
Both chambers regularly operate with far fewer members physically on the floor, relying on the assumption that a quorum exists unless someone raises a point of order. When a quorum call reveals too few members, business stops until enough lawmakers return. The Constitution also allows each chamber to compel the attendance of absent members, and the practical enforcement job falls to the Sergeant at Arms. Senators who leave the capital without permission can be required to pay the expenses the Sergeant at Arms incurs in retrieving them.8U.S. Senate. The Senate Enforces Attendance
Recesses and the Three-Day Rule
When Congress takes a break without ending the session, it enters a recess. The session stays active, procedural clocks keep ticking, and no pending business is reset. Article I, Section 5 imposes one critical limit: neither chamber can adjourn for more than three days without the other chamber’s consent.9Legal Information Institute. Constitution Annotated – Article I, Section 5, Clause 4 – Adjournment of Congress The rule prevents one house from paralyzing the legislative process by refusing to meet.
Pro Forma Sessions
One of the odder features of the calendar is the pro forma session, a brief meeting sometimes lasting only seconds during which no legislation is considered. These exist primarily to block the President from making recess appointments.
Under Article II, the President can fill vacancies without Senate confirmation while the Senate is in recess.10Legal Information Institute. Recess Appointments Power: Overview To prevent that, the Senate schedules pro forma sessions every few days during breaks, keeping any single recess too short to trigger the power. The Supreme Court validated the tactic in NLRB v. Noel Canning (2014), ruling that the Senate is in session whenever it says it is, so long as its rules preserve the capacity to conduct business. The Court also drew practical lines: a recess of three days or fewer is too short for recess appointments, and anything under ten days is “presumptively too short” absent extraordinary circumstances.11Justia. NLRB v. Canning, 573 U.S. 513 (2014) Both parties have embraced the technique regardless of which side controls the Senate or the White House.
How a Session Ends
The formal end of a session is called adjournment sine die, Latin for “without a day,” meaning no return date is scheduled. It terminates all legislative business for that session and requires a concurrent resolution approved by both chambers.12GovInfo. House Practice – Chapter 1: Adjournment It typically happens in late December, though Congress can reconvene before the next session starts if urgent business arises.
Adjournment sine die also carries a consequence for the President’s veto power. Under Article I, Section 7, the President has ten days (Sundays excluded) to sign or veto a bill after receiving it. If Congress stays in session and the President does nothing, the bill becomes law. But if Congress adjourns during that ten-day window and the President hasn’t signed, the bill dies through what’s known as a pocket veto, and Congress gets no chance to override it.13Legal Information Institute. U.S. Constitution Annotated – The Veto Power Timing a bill’s delivery to the President near the end of a session is riskier than it looks.
One boundary worth naming: the President cannot generally adjourn Congress. The single exception in Article II, Section 3 lets the President set an adjournment date when the House and Senate disagree on when to end the session.9Legal Information Institute. Constitution Annotated – Article I, Section 5, Clause 4 – Adjournment of Congress No president has ever used it.
Special Sessions and Joint Sessions
Beyond the regular calendar, two other kinds of gatherings appear in the Constitution.
A special session is one the President calls on “extraordinary occasions” under Article II, Section 3. The President can convene both chambers together or summon just one; the Senate alone has been called to handle nominations and treaties.14Legal Information Institute. U.S. Constitution Annotated – The President’s Legislative Role Calling a special session gives the President no control over what Congress then does. The power has been exercised less often in the modern era because Congress now stays in session most of the year.
A joint session brings both chambers together in the House chamber for a specific purpose. The most familiar example is the State of the Union address. The most constitutionally significant one occurs every four years to count electoral votes for President and Vice President, a process governed by the 12th Amendment and Title 3 of the U.S. Code as substantially updated by the Electoral Count Reform Act of 2022.15EveryCRSReport.com. Joint Session of Congress for Counting Electoral Votes for President16Office of the Law Revision Counsel. 3 USC 1 – Time of Appointing Electors
Lame Duck Sessions
A lame duck session is the period between the November elections and the start of the next Congress on January 3.17United States Senate. Lame Duck Sessions Members who lost their races or chose to retire still hold full voting power during these weeks, and the political dynamics shift because some outgoing lawmakers face less pressure from voters.
These sessions are far from ceremonial. Recent lame duck periods have produced major appropriations packages, the Electoral Count Reform Act and Respect for Marriage Act in 2022, the First Step Act in 2018, the repeal of “Don’t Ask, Don’t Tell” and ratification of the New START treaty in 2010, and the creation of the Department of Homeland Security in 2002.18EveryCRSReport.com. Lame Duck Sessions of Congress, 1935-2022 The urgency comes from the same hard deadline that ends every Congress: any bill not signed into law before the new Congress convenes on January 3 is dead.3Library of Congress. What Happens to a Bill That Has Not Become Law That ticking clock forces compromises that might never happen during the regular session.