Voters kick off the 2012 nominating process to pick the Republican Party's challenger to President Barack Obama with the Iowa caucuses on January 3, which are followed by primaries in New Hampshire and South Carolina on January 10 and January 21.
The three contests are some of the most watched events in the election process. Here are a few facts about them.
* Iowa has been first in the nominating process since 1972 when Iowa Democrats changed the date to meet new rules intended to make delegate selection more transparent and encourage grass-roots participation. Jimmy Carter first drew attention to the caucuses in 1976 when he performed unexpectedly well and went on to take the White House.
* The saying there are only "three tickets out of Iowa" comes from the fact that since 1972 almost no candidate has won their party nomination without coming in third place or better in Iowa. In 2008, Republican nominee John McCain took 4th.
* On average only about 6 percent of eligible voters participate in the Iowa caucuses. In 2008, that jumped to 16.1 percent but was still much lower than the 53.6 percent that took voted in the New Hampshire primaries, according to George Mason University's United States Elections Project.
* The Hawkeye State has chosen Democratic candidates for the White House in five of the last six presidential elections, but political observers say independents could swing the vote. Registered Democrats number about 645,500 to 613,500 Republicans, and almost 718,000 voters were not with a party, according to December data from the Iowa secretary of state.
* In an election focused on the economy, Iowa's 6 percent rate unemployment in October, compared to the national rate of 8.6 percent, is among the lowest in the country.
* Iowa's Hispanic population almost doubled in the past decade to make up about 5 percent of Iowans. About 91 percent were white in 2010, the last U.S. Census shows.
* Before the Iowa caucuses grabbed national attention in the 1970s, the New Hampshire primary was the first test for presidential hopefuls. It is known for political upsets starting with Dwight D. Eisenhower's 1952 win over long-time Republican Senator Robert Taft before winning the presidency.
* New Hampshire primary winners have had mixed success when it comes to getting their party's nomination. John McCain won the Republican primary in 2000 but eventually lost the bid to George W. Bush. In 2008 Hillary Clinton won the Democratic primary but the party nod went to Obama.
* Performance in the Iowa caucuses and the New Hampshire primaries are not consistent. Since 1984, only two candidates have won both.
* The "Live Free or Die" state is not as liberal as some of its New England neighbors. A study released in December by Third Way, a Washington think tank, found the number of registered Democratic voters had fallen 14.6 percent while that of Republicans had declined 13.5 percent.
* Richard Nixon holds the record for winning the most New Hampshire primaries: three.
* The South Carolina Republican primary was set early in the primary calendar in 1980 by Ronald Reagan's campaign coordinator Lee Atwater to give Reagan a boost and southern conservatives more weight in the nominating process.
* The race has since become known as a firewall for establishment frontrunners against insurgent candidates who perform surprisingly well in the earlier contests.
* Since 1980, every winner of the South Carolina Republican presidential primary has gone on to win the party nomination.
* The Palmetto State has gone for Republican candidates in 9 out of the last ten presidential elections.
* Religion resonates with South Carolina voters. A little over 60 percent of South Carolina residents identified as evangelical or mainline Protestant Christian, the Pew Forum's U.S. Religious Landscape Survey in 2008 found.
* With 10.5 percent of the population unemployed, South Carolina has one of the nation's worst unemployment rates.
* South Carolina is among the country's fastest growing states, fueled in part by a burgeoning Hispanic population. In 2010, 5.1 percent of state residents were Hispanic, up from 2.4 percent in 2000, according to the last U.S. Census. African-Americans made up about 28 percent of residents and whites, 66 percent.
(Reporting by Lily Kuo; editing by Alistair Bell)