Lyon county is in the Pennyrile region of Kentucky. The elevation in the county ranges from 305 to 670 feet above sea level.
In 2010 the county population was 8,314 in a land area of 213.84 square miles, an average of 38.9 people per square mile.
The equine population was 400 in the 2012 Kentucky Equine Survey.
Lyon county was named to honor Chittenden Lyon, an early settler.
Much of Lyon county lies within the Land Between the Lakes National Recreation Area.