[3] Its governing structure was not completed at that time, and it was not attached to another county for administrative purposes.

[4][5] The James River flows south-southeastward through the central part of Foster County.

The county terrain consists of low rolling hills, mostly devoted to agriculture, its eastern portion dotted with lakes and ponds.

[6] The terrain slopes to the south and east; its highest point is at its southwestern corner, at 1,942 ft (592 m) ASL.

In terms of ancestry, 54.2% were German, 35.9% were Norwegian, 9.8% were Irish, 5.8% were American, and 5.1% were Swedish.

In only two national elections since 1948 has the county selected the Democratic Party candidate (as of 2024).