Recent polls have had Democratic candidate Hillary Clinton and Republican Ted Cruz leading in Iowa, but a poll released Saturday shows Republican Donald Trump has replaced Cruz in the top spot, the Des Moines Register reports.
But the New York Times says there are challenges in polling for early caucuses because the turnout is variable and voters are divided between many more candidates than remain in the race for later caucuses.
This has the paper saying it wouldn't be "particularly surprising" if Democrat Bernie Sanders or Cruz ended up winning in Iowa.
ABC News says a big turnout Monday night could bode will for Sanders and Trump, who are polling well among those who haven't previously participated in the caucuses.
Cruz and Clinton, though, are faring well among traditional caucus-goers, the New York Times notes.
If a name other than the four candidates mentioned above come out on top from either party, it'll be a "huge story" and "dramatically reshape the race," USA Today says.
Something else to watch for: If anyone places a "strong" third in the Republican field (it would give them some momentum going into the New Hampshire primary on Feb. 9), USA Today notes. Republican Marco Rubio is currently polling in third, and a surprise second-place finish could be very positive for his campaign.
Votes are expected to be tallied Monday night, CNN says perhaps between 11 p.m. and midnight.