Bullion Creek flows eastward into the southwestern corner of the county to discharge into the Little Missouri River.

Billings County terrain consists of rugged semi-arid hills in its western portion, giving way to more level ground in the east.

[7] The South Unit of Theodore Roosevelt National Park lies in the central part of the county, just north of Medora.

In terms of ancestry, 40.6% were German, 19.1% were Ukrainian, 17.7% were Norwegian, 9.3% were Irish, 7.4% were Russian, 5.0% were English, and 0.9% were American.

Billings county gave Ross Perot over twenty percent of the vote in his 1992 and 1996 campaigns.

[15][16] It gave Pat Buchanan approximately six percent when he ran as the Reform Party's candidate in 2000.