Recalling the doubts that "everybody" expressed about his chances in Iowa when he announced his candidacy, Trump said Monday night he was "honored" to come in second place, and he congratulated Cruz. Still, the businessman noted his first-place standing in New Hampshire polls for next Tuesday's primary, looking ahead to the next major test for his campaign.
Florida Sen. Marco Rubio delivered a triumphant address for his third-place finish, saying he will become the Republican nominee.
For his part, Cruz struck a populist tone in his victory speech.
"Iowa has sent notice that the Republican nominee and the next president of the United States will not be chosen by the media, will not be chosen by the Washington establishment, will not be chosen by the lobbyists, but will be chosen by the most incredible, powerful force — where all sovereignty resides in our nation — by we the people, the American people," Cruz declared.
Early entrance poll data had indicated a lead for former Secretary of State Clinton, according to NBC News. In that race, NBC News was allocating 30 of 52 delegates to Clinton, and 21 to Sanders as of 9:42 a.m. ET.
Clinton's campaign indicated to NBC News that it would be declaring victory in the state race, and the former first lady said she was "breathing a big sigh of relief" in her Monday night speech. In that address, Clinton characterized herself as a "progressive who gets things done for people," and as someone who stands in a "long line of American reformers who make up our minds that the status quo is not good enough."
The Republican National Committee, meanwhile, released a statement calling the Democratic Iowa caucus an "unmitigated disaster for Hillary Clinton and the Democrat Party," as the night's results were still too close to call between Sanders and her.
Sanders said just before midnight ET that the race appeared to be in a "virtual tie."
"When I think about what happened tonight, I think the people of Iowa have sent a very profound message to the political establishment, to the economic establishment and — by the way — to the media establishment," he said. "And that is that given the enormous crises facing our country, it is just too late for establishment politics and establishment economics."
Meanwhile, NBC News reported that former Maryland Gov. Martin O'Malley would suspend his campaign Monday night. And former Arkansas Gov. Mike Huckabee tweeted just before 10:30 p.m. ET that he had officially suspended his run for the GOP nomination.
Reports surfaced Monday evening that some precincts received many more caucus-goers than expected, with one county GOP leader telling NBC News that "we are busting at the seams." Entrance poll results from NBC News showed that 43 percent of Republican respondents said Monday's was their first caucus. For the Democrats, 59 percent said they were first-timers.
