[3] The county was created in 1853 and named for United States President James K.

[4] After the Wisconsin Territory was established in 1836, large amounts of American Indian territories were ceded to the United states via the White Pine Treaty, formally known as the treaty of St. Peters, much of the land was covered in vast pine forests, and logging activates began soon after.

As of the 2000 census,[15] there were 41,319 people, 16,254 households, and 11,329 families residing in the county.

25.20% of all households were made up of individuals, and 10.60% had someone living alone who was 65 years of age or older.

The only two times in that span it did not support the Republican candidate were in 1912 when former Republican Theodore Roosevelt won the county as the Progressive candidate and in 1924 when Progressive and native Wisconsinite Robert M. La Follette won the county.

Trump won in 2020 with the exact same margin of victory of over 27% while increasing his vote share to nearly 63%.

In 2024, Trump once again improved on his previous performance, taking nearly 65% of Polk County's vote and defeating Kamala Harris by more than a 30% margin.