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

Numerous tribes lived on the Great Plains including the: Arapaho, Cheyenne, Comanche, Sioux, Ute, Otoe, Kansa, Kiowa, Osage, Omaha, Ponca, Pawnee, and Wichita.

These tribes were sustained by a seemingly inexhaustible supply of buffalo that then numbered in the tens of millions.

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 Oregon-California Trail, the Overland Stage Line, and the Pony Express all ran through Washington County.

[4][5] In 2010, the Keystone-Cushing Pipeline (Phase II) was constructed north to south through Washington County, with much concern over tax exemption and environmental issues when a leak occurs.

Since 1940, only Lyndon Johnson in 1964 has earned forty percent of Washington County's vote as the Democratic Party candidate.

The city of Washington is considered governmentally independent and is excluded from the census figures for the townships.