According to the United States Census Bureau, the county has a total area of 246 square miles (640 km2), of which 240 square miles (620 km2) is land and 6.3 square miles (16 km2) (2.6%) is water.[5] The county's northern border with Ohio is formed by the Ohio River.
U.S. Decennial Census[7] 1790-1960[8] 1900-1990[9] 1990-2000[10] 2010-2020[1]
As of the census of 2000, there were 16,800 people, 6,847 households, and 4,697 families residing in the county. The population density was 70 per square mile (27/km2). There were 7,754 housing units at an average density of 32 per square mile (12/km2). The racial makeup of the county was 90.88% White, 7.16% Black or African American, 0.15% Native American, 0.37% Asian, 0.02% Pacific Islander, 0.57% from other races, and 0.85% from two or more races. 0.95% of the population were Hispanic or Latino of any race.
There were 6,847 households, out of which 31.30% had children under the age of 18 living with them, 54.20% were married couples living together, 11.10% had a female householder with no husband present, and 31.40% were non-families. 27.60% of all households were made up of individuals, and 12.80% had someone living alone who was 65 years of age or older. The average household size was 2.41 and the average family size was 2.92.
In the county, the population was spread out, with 24.10% under the age of 18, 8.00% from 18 to 24, 28.50% from 25 to 44, 23.90% from 45 to 64, and 15.50% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 93.70 males. For every 100 females age 18 and over, there were 89.50 males.
The median income for a household in the county was $30,195, and the median income for a family was $37,257. Males had a median income of $30,718 versus $21,216 for females. The per capita income for the county was $16,589. About 12.90% of families and 16.80% of the population were below the poverty line, including 23.60% of those under age 18 and 13.70% of those age 65 or over.
Mason County was at the time of the Civil War the easternmost of the strongly secessionist Bluegrass bloc.[11] Mason was in fact the most easterly Kentucky county to be represented at the Russellville Convention of 1861 to discuss the secession of Kentucky from the Union.
Mason County's secessionist sentiment meant that it voted Democratic consistently up until the 1950s, with the exception of the 1928 election when strong local anti-Catholic sentiment against Al Smith allowed Herbert Hoover to carry the county. Since 1996 the county has shifted more strongly Republican in US presidential elections.
United States presidential election results for Mason County, Kentucky[12]
Albert Sidney Johnston, Commander of the Army of the Republic of Texas, Secretary of War for Texas, Commander of the Western Department for the Confederacy. Died at the Battle of Shiloh.
Judge Roy Bean, Famous "Hanging Judge" of Texas (Law West of the Pecos).
^Copeland, James E.; 'Where Were the Kentucky Unionists and Secessionists'; The Register of the Kentucky Historical Society, volume 71, no. 4 (October 1973), pp. 344-363