[3][4][5] It was named for American Civil War General William Tecumseh Sherman.

The terrain of Sherman County consists of rolling hills, sloping to the southeast.

The area is partially dedicated to agriculture, with limited use of center pivot irrigation.

The Middle Loup River flows south-southeastward through the eastern central part of the county.

The western portions are drained by Clear Creek and Muddy Creek, which merge in the SW part of the county and exit the south boundary line, to discharge into Middle Loup River at a point southeast of the county's SE corner.

As of the census of 2000, Americans of Polish ancestry comprised 29.6% of Sherman County's population.