In 1871, the Atchison, Topeka and Santa Fe Railway extended a main line from Emporia to Newton.

[6] The county developed quickly, with churches, schools, and businesses established within a few years of its founding.

Despite early hardship from prairie fires, storms, and the devastating grasshopper plague of 1874, Harvey County rebounded with strong agricultural output and infrastructure improvements.

The county's abundant water resources, fertile farmland, and natural materials like gypsum and limestone further strengthened its economy.

Harvey County is part of the Wichita, KS Metropolitan Statistical Area.

Following amendment to the Kansas Constitution in 1986, the county remained a prohibition, or "dry", county until 1996, when voters approved the sale of alcoholic liquor by the individual drink with a 30% food sales requirement.

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