For many millennia, the Great Plains of North America was inhabited by nomadic Native Americans.

In 1802, Spain returned most of the land to France, but keeping title to about 7,500 square miles.

In 1803, most of the land for modern day Kansas was acquired by the United States from France as part of the 828,000 square mile Louisiana Purchase for 2.83 cents per acre.

In 1887, the Chicago, Kansas and Nebraska Railway built a branch line north–south from Herington to Caldwell.

[4] This branch line connected Herington, Lost Springs, Lincolnville, Antelope, Marion, Aulne, Peabody, Elbing, Whitewater, Furley, Kechi, Wichita, Peck, Corbin, Wellington, Caldwell.

[6] Sumner County is part of the Wichita, KS Metropolitan Statistical Area.

However, in 1992 independent candidate Ross Perot came within two percent of winning the county against George H. W. Bush.

Following amendment to the Kansas Constitution in 1986, Sumner County remained a prohibition, or "dry", county until 1992, when voters approved the sale of alcoholic liquor by the individual drink with a 30 percent food sales requirement.

† means a community is designated a Census-Designated Place (CDP) by the United States Census Bureau.

The cities of Caldwell and Wellington are considered governmentally independent and are excluded from the census figures for the townships.