[1] The county was named after Alfred Gray, a 19th century Kansas politician.

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

[5] Since 2001, NextEra Energy Resources has operated the largest wind farm in Kansas—170 turbines with a generating capacity of 110 megawatts—on a 12,000-acre (49 km2) site near Montezuma.

21.20% of all households were made up of individuals, and 9.40% had someone living alone who was 65 years of age or older.

Gray County has by far the highest percentage of adherents of the Church of God in Christ, Mennonite in the US.

The last time a Democratic candidate carried this county was in 1976 by Jimmy Carter.

Although the Kansas Constitution was amended in 1986 to allow the sale of alcoholic liquor by the individual drink with the approval of voters, Gray County has remained a prohibition, or "dry", county.