Grayson county is in the Western Coal Field region of Kentucky. The elevation in the county ranges from 395 to 963 feet above sea level.
In 2010 the county population was 25,746 in a land area of 496.70 square miles, an average of 51.8 people per square mile.
The equine population was 3,000 in the 2012 Kentucky Equine Survey.
Grayson county was named for Colonel William Grayson, who was an aide to General George Washington and a United States Senator from Virginia and who owned extensive land in Kentucky. He was a grandfather of William Grayson Carter, for whom Carter county was named.