"Bon Homme" was first used by Lewis and Clark in 1804 as the name for a 2,000 acre island in the Missouri River.

[6] The village of Bon Homme was the original county seat until 1885, when it moved to Tyndall.

[7] Bon Homme County is the point of origin for the Siberian alien, Kali tragus, a type of tumbleweed, first reported here in 1877, probably introduced in a shipment of flax seed from Ukraine.

The west boundary line of the county is roughly defined by Choteau Creek, which flows southward to discharge in the river.

The county terrain consists of low rolling hills, sloping to the river valley; most of the area is devoted to agriculture.

The terrain's highest point is the county's NW corner, at 1,883 ft (574 m) ASL.

In terms of ancestry, 48.6% were German, 20.6% were Czech, 11.7% were Dutch, 7.8% were Irish, 6.1% were Norwegian, and 1.7% were American.