Question: Clayton in the state where the first caucus is held for each presidential campaign are located in what county?

full_context: Document 1: United States presidential primary: Delegates to the national convention were usually selected at state conventions whose own delegates were chosen by district conventions. Sometimes they were dominated by intrigue between political bosses who controlled delegates; the national convention was far from democratic or transparent. Progressive Era reformers looked to the primary election as a way to measure popular opinion of candidates, as opposed to the opinion of the bosses. Florida enacted the first presidential primary in 1901. The Wisconsin direct open primary of 1905 was the first to eliminate the caucus and mandate direct selection of national convention delegates. In 1910, Oregon became the first state to establish a presidential preference primary, which requires delegates to the National Convention to support the winner of the primary at the convention. By 1912, twelve states either selected delegates in primaries, used a preferential primary, or both. By 1920 there were 20 states with primaries, but some went back, and from 1936 to 1968, 12 states used them.
Document 2: 2004 United States presidential election: The following week, John Edwards won the South Carolina primary and finished a strong second in Oklahoma to Clark. Lieberman dropped out of the campaign the following day. Kerry dominated throughout February and his support quickly snowballed as he won caucuses and primaries, taking in a string of wins in Michigan, Washington, Maine, Tennessee, Washington, D.C., Nevada, Wisconsin, Utah, Hawaii, and Idaho. Clark and Dean dropped out during this time, leaving Edwards as the only real threat to Kerry. Kucinich and Sharpton continued to run despite poor results at the polls.
Document 3: 2004 United States presidential election: By the January 2004 Iowa caucuses, the field had dwindled down to nine candidates, as Bob Graham had dropped out of the race. Howard Dean was a strong front-runner. However, the Iowa caucuses yielded unexpectedly strong results for Democratic candidates John Kerry, who earned 38% of the state's delegates and John Edwards, who took 32%. Former front-runner Howard Dean slipped to 18% and third place, and Richard Gephardt finished fourth (11%). In the days leading up to the Iowa vote, there was much negative campaigning between the Dean and Gephardt camps.
Document 4: Interregional Primary Plan: The Interregional Primary Plan is a proposed reform to the United States primary calendar supported by Representative Sandy Levin and Senator Bill Nelson, both Democrats. The plan would break the country into six regions. From those regions, one subregion - either a single state or a group of smaller states - would vote on each primary date (e.g., all A states,) with the entire country having held its primaries after the sixth set of primaries votes. Each state would vote first once every twenty-four years, with the first set of primaries determined by lottery and cycled thereafter.
Document 5: Dow City, Iowa: Dow City is a city in Crawford County, Iowa, United States, along the Boyer River. The population was 510 at the 2010 census.
Document 6: 2004 United States presidential election: In March's Super Tuesday, Kerry won decisive victories in the California, Connecticut, Georgia, Maryland, Massachusetts, New York, Ohio, and Rhode Island primaries and the Minnesota caucuses. Dean, despite having withdrawn from the race two weeks earlier, won his home state of Vermont. Edwards finished only slightly behind Kerry in Georgia, but, failing to win a single state other than South Carolina, chose to withdraw from the presidential race. Sharpton followed suit a couple weeks later. Kuninch did not leave the race officially until July.
Document 7: 2020 United States presidential election: The United States presidential election of 2020, scheduled for Tuesday, November 3, 2020, will be the 59th quadrennial U.S. presidential election. Voters will select presidential electors who in turn will either elect a new president and vice president through the electoral college or re-elect the incumbents. The series of presidential primary elections and caucuses are likely to be held during the first six months of 2020. This nominating process is also an indirect election, where voters cast ballots selecting a slate of delegates to a political party's nominating convention, who then in turn elect their party's presidential nominee.
Document 8: Clayton, Missouri: Clayton is a city in and the county seat of St. Louis County, Missouri, United States, and borders the city of St. Louis. The population was 15,939 at the 2010 census. The city was organized in 1877 and is named after Ralph Clayton, who donated the land for the courthouse. The city is known for its multiple skyscrapers in its business district.
Document 9: Clayton Township, Adams County, Illinois: Clayton Township is one of twenty-two townships in Adams County, Illinois, United States. As of the 2010 census, its population was 1,027 and it contained 465 housing units.
Document 10: Clay City Township, Clay County, Illinois: Clay City Township is one of twelve townships in Clay County, Illinois, USA. As of the 2010 census, its population was 1,287 and it contained 649 housing units.
Document 11: United States presidential primary: February 1: Iowa caucus (both parties) February 9: New Hampshire primary (both parties) February 20: Nevada Democratic caucuses and South Carolina Republican primary February 23: Nevada Republican caucuses February 27: South Carolina Democratic primary March 1: Super Tuesday: Primaries / caucuses for both parties in several states
Document 12: Summit Township, Clay County, Iowa: Summit Township is a township in Clay County, Iowa, USA. As of the 2000 census, its population was 452. Spencer Municipal Airport is located in the township.
Document 13: 2020 United States presidential election: The United States presidential election of 2020, scheduled for Tuesday, November 3, 2020, will be the 59th quadrennial U.S. presidential election. Voters will select presidential electors who in turn will either elect a new president and vice president through the electoral college or reelect the incumbents. The series of presidential primary elections and caucuses are likely to be held during the first six months of 2020. This nominating process is also an indirect election, where voters cast ballots selecting a slate of delegates to a political party's nominating convention, who then in turn elect their party's presidential nominee.
Document 14: Clayton, Iowa: Clayton is a city in Clayton County, Iowa, United States. The population was 43 at the 2010 census, down from 55 at the 2000 census. Clayton is located directly on the Mississippi River and is only accessible by a very steep road. Many people have summer homes in Clayton due to its proximity to the Mississippi River.
Document 15: Everly, Iowa: Everly is a city in Clay County, Iowa, United States. The population was 603 in the 2010 census, a decline from 647 in the 2000 census. The Ocheyedan River flows to the south and west of the city.
ground_truth: Clayton County
sub_queries: where is the first caucus held for each presidential campaign Answer: Iowa
Clayton, Iowa >> located in the administrative territorial entity Answer: Clayton County