The former president has seen his support erode among most demographic groups since his Democratic rival in the November 5 election, Vice President Kamala Harris, replaced President Joe Biden atop the Democratic ticket.
Trump is scheduled to speak on Saturday in Mosinee, a town of about 4500 people.
The town is near Wausau, a small city of about 40,000, but hours from the state's major population centres, namely Milwaukee and Madison.
Marathon County, where Mosinee is located, used to be politically competitive, having voted for Democratic nominee Barack Obama in 2008.
Since then, the county has veered right, having favoured Trump in 2016 and 2020, both times by about 18 points.
Nationally, Harris is leading Trump among Hispanic voters by 13 percentage points, according to the latest Reuters/Ipsos poll, conducted in August, while Biden led that demographic by just five points in May.
She has also boosted her support among Black Americans, outperforming Biden by seven points among that demographic.
But she has barely moved the needle among white voters, those same polls show.
Whites without a college degree, long the linchpin of Trump's coalition, still favour the former president by 25 points, according to the latest Reuters/Ipsos poll.
Donald Trump swept the "rust belt" states when he won the 2016 election over Hilary Clinton. (AP PHOTO)
They favoured Trump by 29 points when he was running against Biden.
That relative resilience among white voters represents an electoral bright spot for Trump, and several Trump advisers and allies have told Reuters in recent weeks that maintaining the former president's margins within that demographic will be crucial if he is to defeat Harris.
That is especially true in the northern "rust belt" states, Wisconsin included, which skew white and have large rural populations.
Trump relied heavily on these voters when he swept the rust belt's swing states on the way to his 2016 victory over Democratic nominee Hillary Clinton.
Biden won the White House in 2020 in part by bringing some of these voters back into the Democratic Party.
While the Trump campaign has identified Hispanics and Black men as a key area of growth for the Republican Party, much of Trump's campaigning in recent weeks has taken place in small cities and towns in the Rust Belt that are not diverse.
Trump's running mate, Ohio US Senator JD Vance, is expected to hit relatively rural areas of the Rust Belt particularly hard in the final weeks before the election, two Trump advisers told Reuters.
