Estill county was formed in 1808. It is located in the Eastern Knobs and Eastern Coal Field regions of the state. The elevation in the county ranges from 566 to 1511 feet above sea level. In 2010 the county population was 14,672 in a land area of 253.08 square miles, an average of 58.0 people per square mile.

The county seat is Irvine.