Four communities aspired to be chosen as the permanent county seat: Ashford, Harrisburg, Freeport, and Banner.

[5] The initial settlement of the area was by cattle ranchers, drawn by good pastures in the Pumpkin Creek valley.

In the late 1880s, these open-range ranchers were displaced by an influx of settlers; by 1890, almost every quarter-section (160 acres, or 65 ha) was claimed by homesteaders.

The 1904 passage of the Kinkaid Act, which allowed homesteaders to claim 640 acres (260 ha) brought a new wave of settlers; however, even these larger tracts were often insufficient to support a family, and many of the Kinkaid claims were eventually sold to established cattle ranchers.

[7] Rainfall in Banner County is light and variable; the average yearly precipitation at the Harrisburg weather station is 14.3 inches (360 mm).

Construction of the launch sites, and upgrading of the roads leading to them, led to an economic boom in western Nebraska.

Beginning in 1963, the Atlas series was replaced by Minuteman missiles, which used solid instead of liquid fuel, and which were launched from underground silos.

Over geologic history, it was eroded by Pumpkin Creek and other watercourses, and much of the county now lies below the original High Plains level.

[13] The western edge of Banner County abuts the eastern border of the state of Wyoming.

About 60% of Banner County is given over to farming: chiefly winter wheat and rangeland,[22] but also corn, beans, sugar beets, potatoes, sunflowers, rapeseed, and millet.

[2] In response to groundwater depletion and drought, the Natural Resources Conservation Service has developed a system of cash incentives for farmers in the Pumpkin Creek watershed who convert irrigated cropland to dryland farming.

A 2010 sale of oil leases yielded record prices in Banner and Kimball counties.

This has only strengthened in recent years, with Republicans winning over 80% of the vote in each of the past seven elections, dating back to 2000.