Letcher county is in the Eastern Coal Field region of Kentucky. The elevation in the county ranges from 940 to 3720 feet above sea level.
In 2010 the county population was 24,519 in a land area of 337.91 square miles, an average of 72.6 people per square mile.
The equine population was 200 in the 2012 Kentucky Equine Survey.
Letcher county was named for Governor Robert P. Letcher.
Letcher county was the setting for the early twentieth century novels The Little Shepherd of Kingdom Come and The Trail of the Lonesome Pine of John Fox, Jr. Kingdom Come State Park is located in the southwest of the county on the border with Harlan county. Lilley Cornett Woods, one of the largest tracts of protected old-growth forest in the state, is located in the county.