[2] The county was formed in 1806 from the western part of Lincoln County[3] and named for Colonel William Casey, a pioneer settler who moved his family to Kentucky in 1779.

[5] In 2015, County Clerk Casey Davis received national press when he announced he would deny same-sex marriage licenses, as a show of solidarity with fellow county clerk Kim Davis (no relation), who was criticized and later jailed for doing the same thing in Rowan County, Kentucky.

[7] The highest point in Casey County is Green River Knob at 1,789 feet (545 m).

26.80% of all households were made up of individuals, and 12.60% had someone living alone who was 65 years of age or older.

[13] Casey County has one of the longest streaks of voting for Republican Party candidates in presidential elections in Kentucky & nationwide, with its candidates gaining the majority of the vote by wide margins in every election from 1916 on.

No Democratic presidential candidate has won more than 30% of the county's vote since Jimmy Carter in 1976.