<P> The first binding event , in which a candidate can secure convention delegates , is traditionally the Iowa caucus , usually held in late January or early February of the presidential election year . It is generally followed by the New Hampshire primary , the first primary by tradition since 1920 and by New Hampshire state law . New Hampshire law states the primary shall be held `` on the Tuesday at least seven days immediately preceding the date on which any other state shall hold a similar election . '' The Iowa caucuses are not considered to be `` a similar election '' under New Hampshire 's law because the former uses caucuses instead of primary elections . Should any other state move its primary too close to New Hampshire 's , or before , the New Hampshire Secretary of State is required to reschedule the primary accordingly . </P>
by tradition which state 's caucus is the first presidential contest held every four years
Iowa