The signs are everywhere that Sauk County, Wis., is a divided place.

Neighboring lawns display placards for Vice President Kamala Harris and former President Donald J. Trump. After a recent heated barroom argument, the bartender at the Square Tavern in Baraboo, the county seat, posted handwritten notes admonishing customers along the giant mirror behind the bar: “No Politics and No Religion.”

Sauk County has been a presidential bellwether in recent years, voting for the winner in the past four elections. Like everywhere, voters here are split over which candidate will lower the cost of groceries and housing and who can best address issues like crime, abortion and especially immigration.

With the country now contemplating whether to support a Black woman for president and Mr. Trump stirring animosity, residents are also complaining about the divisive racial undercurrent in the campaign — an issue that could influence the way voters here and in other swing state communities decide.

Sauk County, which is mostly white with a small but growing nonwhite population, has been roiled by its own racial skirmishes in recent years.

This summer, a county board meeting turned hostile over worries that refugees might someday settle nearby.

In May, at a high school graduation ceremony, a white parent rushed the stage to shove aside a Black school superintendent.