[2] The county was formed in 1877[3] and named after General George Armstrong Custer,[4] who was killed at the Battle of Little Bighorn.

The region was once part of the Sioux territory, but following the Indian Wars, particularly after the Battle of the Little Bighorn, the land was opened for homesteading.

These early pioneers encountered formidable challenges like extreme weather conditions, isolation, and the task of farming in what was considered the Great American Desert.

They constructed sod houses due to the absence of timber, and settlements were strategically placed near water sources.

[6] The Burlington Railroad's extension through the county in the early 1880s significantly boosted settlement by providing a means for transportation and trade.

The railroad not only facilitated the influx of settlers but also allowed for the export of agricultural products, marking the transition from cattle ranching to more diverse farming practices.

[7] Agriculture shifted from cattle ranching to diversified farming, with wheat and corn becoming prominent crops.