The primaries and caucuses that will lead to the selection of a Republican presidential nominee to challenge Democratic President Barack Obama began in Iowa on Jan. 3, 2012.

See also: 2012 Primary Results

The primary dates continue for nearly six months, until Utah holds the last of the Republican primaries in the nation on June 26, according to the Federal Election Commission.

Primaries Versus Caucuses

All told, 36 states and Washington, D.C., hold primaries to nominate delegates to the Republican and Democratic nominating conventions.

Fourteen other states run caucuses.

The 14 states that hold caucuses are Alaska, Colorado, Hawaii, Idaho, Iowa, Kansas, Maine, Minnesota, Missouri, Nevada, North Dakota, Utah, Washington and Wyoming.

See Also:3 Ways to Bypass the Electoral College

Primaries are elections held at the state level in which voters nominate a candidate affiliated with one political party to run against a candidate who is affiliated with another political party in a later, general election.

Caucuses, meantime, are less former meetings held at the local level in which registered members of a political party gathered to debate and express support for candidates of their choice.

Candidates for President

Obama, who was first elected president in 2008, will be unopposed for a second term in the Democratic presidential primaries and caucuses in 2012. The party will hold its convention in Charlotte, N.C., the week of Sept. 3, 2012.

But nine Republican hopefuls initially began slugging it out in primaries and caucuses across 50 states leading up to the Republican National Convention in Tampa Bay in late August.

Some dropped out before the convention.

See Also:History of Democratic and Republican Conventions

The Republican contenders are former House Speaker Newt Gingrich; U.S. Rep. Ron Paul of Texas; former Louisiana Gov. Buddy Roemer; former Massachusetts Gov. Mitt Romney; and former U.S. Sen. Rick Santorum of Pennsylvania.

Republicans who dropped out early in the process are U.S. Rep. Michele Bachmann of Minnesota; former Godfather's Pizza chief executive officer Herman Cain; former Minnesota Gov. Tim Pawlenty; former Utah Gov. Jon Huntsman; and Texas Gov. Rick Perry;

Here are the caucus and primary dates, according to the FEC:

January

• Jan. 3 - Iowa Republican and Democratic caucuses
• Jan. 10 - New Hampshire Republican and Democratic primaries
• Jan. 21 - Nevada Democratic caucus, South Carolina Republican primary
• Jan. 28 - South Carolina Democratic primary
• Jan. 31 - Florida Republican and Democratic primaries

February

• Feb. 4 - Nevada Republican caucus
• Feb. 4 through Feb. 11 - Maine Republican caucus
• Feb. 7 - Colorado Republican caucus; Minnesota Republican and Democratic caucuses; Missouri Democratic primary
• Feb. 28 - Arizona and Michigan Republican and Democratic primaries

March

• March 3 - Washington Republican caucus
• March 6 - Alaska, Idaho and North Dakota Republican caucuses; Colorado Democratic caucus; Georgia, Massachusetts, Oklahoma, Tennessee, Texas, Vermont and Virginia Republican and Democratic primaries
• March 6 through 10 - Wyoming Republican caucuses
• March 7 - Hawaii Democratic caucus
• March 10 - Kansas Republican caucus
• March 11 - Maine Democratic caucus
• March 13 - Alabama and Mississippi Republican and Democratic primaries; Hawaii Republican caucus; Utah Democratic caucus
• March 17 - Missouri Republican caucus
• March 20 - Illinois Republican and Democratic primaries
• March 24 - Louisiana Republican and Democratic primaries

April

• April 3 - Washington, D.C., Maryland and Wisconsin Republican and Democratic primaries
• April 14 - Idaho, Kansas and Wyoming Democratic caucuses
• April 15 - Alaska and Washington Democratic caucuses
• April 24 - Connecticut, Delaware, New York, Pennsylvania and Rhode Island Republican and Democratic primaries

May

• May 8 - Indiana, North Carolina and West Virginia Republican and Democratic primaries
• May 15 - Nebraska and Oregon Republican and Democratic primaries
• May 22 - Arkansas and Kentucky Republican and Democratic presidential primaries

June

• June 5 - California, Montana, New Jersey, New Mexico and South Dakota Republican and Democratic presidential primaries; North Dakota Democratic caucus
• June 12 - Ohio Republican and Democratic presidential primaries
• June 26 - Utah Republican primary