The President goes to Minnesota, and his rival goes to Ohio and Pennsylvania.
On Tuesday, the candidates held their first debate held in a tense atmosphere: participants interrupted each other and exchanged recriminations.
Trump did not take the opportunity to denounce white supremacists, and again evaded a direct answer to the question of whether he would accept any election results, which gave Biden new material for criticism.
The debate has rattled investors, adding to concerns that disputed election results could complicate the transfer of power. Ahead of the opening of trading, futures on US stock indexes are showing a decline.
According to the University of Florida, more than 1.3 million voters in 15 states have already voted in the United States.
On Wednesday, Trump is hosting a fundraising event and campaign rally in Minnesota.
Biden and his wife, Jill, will tour half-dozen cities in Eastern Ohio and Western Pennsylvania, including counties where Trump won in 2016.
Many strategists believe that Pennsylvania is the most important of the six states that can determine the outcome of an election. These states also include Arizona, Florida, Michigan, North Carolina, and Wisconsin. According to the latest Reuters/Ipsos poll, Biden leads by a narrow margin in Pennsylvania.
Ohio, where Trump beat Democrat Hillary Clinton by 8 percent in 2016, is one of the states that lean in favor of the Republicans, but Biden hopes to persuade.
In national opinion polls, Biden leads by a modest but steady margin, but the gap between candidates is smaller in crucial swing states.