Mahnomen, East Polk, and Becker counties constitute one of northwestern Minnesota's biggest cattle-raising areas.

The county terrain consists of low rolling hills, carved with drainages.

The eastern part of the county is dotted with lakes and ponds and largely wooded.

[5] The county slopes to the west and north, with its highest point near the middle of the east border, at 1,825 ft (556 m) ASL.

For several decades, Mahnomen County voters have tended to vote Democratic.

As of 2020, the county has selected the Democratic candidate in six of the past ten presidential elections.

The county also voted Republican by a wider margin in the 2022 Midterm Elections, potentially signifying a realignment.