The name was selected in a contest and reflects the predominant landscape of the region.

[4] The county was the site of the 1938 Custer Creek train wreck that killed 47 people and injured 75.

[citation needed] As of the 2010 census, there were 1,179 people, 551 households, and 342 families in the county.

In terms of ancestry, 44.7% were German, 18.6% were Norwegian, 14.1% were American, 11.8% were Irish, and 9.5% were English.

Voters in Prairie County have voted for Republican Party candidates in all national elections since 1948 (as of 2024).