The poll, out Monday, found that Biden has 51% support, compared to Sanders’ 36% among likely Democratic primary voters in the state with the most delegates up for grabs on Tuesday.
Biden’s large margin in Michigan follows his Super Tuesday victories, when he regained ground after Sanders won three of the first four early contests.
Monmouth notes that Michigan polls ahead of the 2016 primary were off by a large margin, overstating Hillary Clinton’s support in the state by double digits. Sanders won the state by a narrow margin.
A previous New York Times/Siena poll taken last October found Biden just barely leading the crowded Democratic field in Michigan.
Per the Monmouth poll, half of the Democratic primary voters in Michigan voters are firmly decided, while 23% are open to a different candidate, and 17% have already voted.
Both Biden and Sanders lead President Donald Trump in hypothetical general election matchups, according to the poll, with Biden leading the President by 7 percentage points and Sanders by 5 percentage points among registered voters of all parties.
A February Quinnipiac University poll in Michigan also found Biden and Sanders ahead of Trump by single digits among registered voters.
Still, a majority of Michigan voters (57%) believe Trump will be reelected in November, while 32% think he will lose to the Democratic candidate.
The Monmouth University poll was conducted March 5 through 8 among a random statewide sample of 977 Michigan voters reached on landlines or cellphones by a live interviewer. Results for the full sample have a margin of sampling error of plus or minus 3.1 percentage points. For results among the 422 registered voters who are Democrats or Democratic-leaning independents, it is plus or minus 4.8 percentage points.