A sponsor or patron is a person, usually a legislator, who presents a bill or resolution for consideration. Those who support it are known as cosponsors or copatrons.
A sponsor in the United States Congress is the first member of the House or Senate to be listed among the potentially numerous lawmakers who introduce a bill for consideration.  Committees are occasionally identified as sponsors of legislation as well. A sponsor is also sometimes called a "primary sponsor." 
It should not be assumed that a bill's sponsor actually drafted it. The bill may have been drafted by a staff member, by an interest group, or by others.  In the Senate, multiple sponsorship of a bill is permitted. 
In contrast to a sponsor, a "cosponsor" is a senator or representative who adds his or her name as a supporter to the sponsor's bill. An "initial cosponsor" or "original cosponsor" is a senator or representative who was listed as a cosponsor at the time of a bill's introduction, rather than added as a cosponsor later on.  A cosponsor added later is known as an "additional cosponsor".  Some bills have hundreds of cosponsors. 
- Sponsor/Cosponsor Summaries from the Library of Congress: (2007-2008), (2005-2006), (2003-2004), (2001-2002), (1999-2000), (1997-1998), (1995-1996), (1993-1994), (1991-1992), (1989-1990), (1987-1988), (1985-1986), (1983-1984), (1981-1982), (1979-1980), (1977-1978), (1977-1978), and (1975-1976).
- "Bills Introduced / Bills Referred / Sponsor (CongressionalGlossary.com)". hobnob blog. TheCapitol.net. Retrieved 3 May 2014.
- Johnson, Charles. "How Our Laws Are Made", United States House of Representatives (2003).
- Sagers. Chris. “A Statute by Any Other (Non-Acronomial) Name Might Smell Less Like S.P.AM., or, The Congress of the United States Grows Increasingly D.U.M.B.”, Cleveland-Marshall Legal Studies Paper No. 08-151 (2008): "bills may also be drafted by constituents or interest groups, by state legislatures ('memorializing' Congress to enact federal laws), by administrative agencies, or by commissions appointed by the president or a cabinet member."
- Fitch, Brad. “Media Relations Handbook for Agencies, Associations, Nonprofits, And Congress” (TheCapitol.Net 2004): “Some bills have hundreds of cosponsors, since members can easily add their support to any bill introduced and sometimes do it verbally without notifying staff.”