[1] The county was named for Sergeant Marion Harper of the 2nd Kansas Cavalry, who died in battle during the American Civil War.

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

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.

The petition for organization used several names out of a Cincinnati city directory to represent as residents of Harper County.

Since Bluff City could not be shown to have existed, Anthony was designated as the temporary county seat.

[6] Due to new and high-paying jobs at area oil fields and wind farms, Harper County experienced an economic boom; as of 2012, rental housing and office space in towns such as Danville, Harper, and Anthony had more than quadrupled in price, in properties ranging from double-wide trailers to a Carnegie library.

[7] However, by 2016, the oil fracking boom had largely played out and the economies of Harper and adjacent counties suffered under the impact.

[8] Earthquakes, due to induced seismicity from injection wells, had also substantially reduced in frequency and intensity, thanks to a Kansas Corporation Commission order mandating cutbacks in volumes and pressures.

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