Putnam County is part of the Ottawa, IL Micropolitan Statistical Area.

[12] In terms of ancestry, 46.5% were German, 16.7% were Irish, 16.3% were Italian, 10.9% were Polish, 10.1% were English, 5.1% were Swedish, and 3.5% were American.

[14] Putnam County is divided into four townships: Prior to 1988, Putnam County was a Republican Party stronghold in presidential elections, backing the Republican candidate in all but three elections from 1892 to 1984.

From 1988 to 2012, the county consistently backed Democratic Party presidential candidates, but none fared better than Illinois resident Barack Obama's 56.9% in 2008.

This foreshadowed what was to come in the 2016 election, as the county swung 21.8 points Republican to back Donald Trump over Illinois-born Hillary Clinton by a margin of 19.9%.