It took an extra six weeks, but Joe Biden finally won Ohio’s Democratic presidential primary.

The AP called the race for the former vice president soon after unofficial election results started pouring in on Tuesday night from a contest that was conducted almost entirely by mailed in absentee ballots.

According to early results, the presumptive Democratic presidential nominee had a large lead over Sen. Bernie Sanders of Vermont, who was Biden’s last remaining rival who suspended his campaign and endorsed the former vice president earlier this month.

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In-person voting in Ohio’s primary was originally scheduled for March 17 – but was scrapped at the last minute due to coronavirus pandemic health concerns. The three other states with primaries on the same day – Florida, Illinois and Arizona – all held their contests.

Under a bill passed by Ohio’s legislature and signed into law by Republican Gov. Mike DeWine, postcards were sent to every registered voter to explain how they could obtain a vote-by-mail application. Ballots had be postmarked by April 27 to be counted. Voters also had the option to drop ballots off at county boards of elections before 7:30 p.m. Tuesday. In-person voting was only available on Tuesday to a limited number of individuals – mostly those with disabilities.

Ohio election officials reported that as of Monday more than 1.9 million Ohioans had requested absentee ballots and that more than 1.4 million had already been received.

With the coronavirus outbreak forcing social distancing and keeping most Americans in their homes in hopes of preventing a spread of the virus that causes the deadly COVID-19 disease, the Democratic presidential nomination calendar has been upended. Ohio was one of the first states holding primaries or caucuses in mid-March and beyond to delay their contest or hold it nearly entirely by mail.

One exception was Wisconsin, where three weeks ago, after a bitter partisan fight won by Republicans, the state became the first in the nation to hold in-person voting during the pandemic.

With the state under a stay-at-home order, thousands of poll workers refused to show up over health concerns, forcing many cities and towns to cut the number of polling stations. Milwaukee was down to just five polling sites from the original 180.

Even though the National Guard stepped in to provide some assistance, long lines instantly formed as the polls opened, with many voters waiting hours to cast a ballot. In many instances, social distancing was extremely difficult to maintain.

Democrats in Wisconsin and across the nation decried the rulings to carry on with the in-person voting during the pandemic. As of Tuesday, at least 40 people who said they voted in-person or were poll workers in Wisconsin’s April 7 primary tested positive for the coronavirus, state health officials said.

In Ohio, Biden’s expected to win the lions share of the 136 delegates up for grabs. Besides the Democratic presidential primary, there was also Republican presidential primary contest, as well as some down-ballot races.

Fox News' Allie Raffa contributed to this report