Spencer county is in the Outer Bluegrass region of Kentucky. The elevation in the county ranges from 420 to 880 feet above sea level.
In 2010 the county population was 17,061 in a land area of 186.68 square miles, an average of 91.4 people per square mile.
The equine population was 1,000 in the 2012 Kentucky Equine Survey.
Spencer county was named to honor Spears Spencer, who served in the Kentucky militia and was killed at the Battle of Tippecanoe in 1811.