[1] The county is named in honor of Philip Kearny, a general during the American Civil War that died during the Battle of Chantilly.

[4] Prior to settlement, Kearny County was unorganized territory that was entirely "cow country," undeveloped and with no agricultural activity except for cattlemen grazing their herds.

The region was part of the vast open range found in the American West at that time.

[5] In the mid-1880s, homesteaders began pouring into the area, initiating conflicts with the existing cattle ranching industry as they claimed land and fenced off the open range.

[6] The arrival of homesteaders was seen as both an opportunity for development but also a threat to the cattle industry's way of life, with numerous allegations of ranchers trying to drive settlers out by destroying crops and setting prairie fires appearing in local newspapers.

Only four counties (Hamilton, Greeley, Wallace, and Sherman), all of which border Colorado, observe Mountain Time.

[8] Kearny County is included in the Garden City, KS Micropolitan Statistical Area.

Following amendment to the Kansas Constitution in 1986, the county remained a prohibition, or "dry", county until 1988, when voters approved the sale of alcoholic liquor by the individual drink with a 30 percent food sales requirement.