It was named for Alexander Hamilton, first United States Secretary of the Treasury.

[6] According to the Secretary of State's Office, as of February 28, 2023, Republicans hold a plurality of registered voters in Hamilton County for the first time in over a century.

The county has radically shifted from being a Democratic stronghold to becoming a Republican one during the 21st century.

The 2020 United States census counted 14,004 people, 4,690 households, and 3,072 families in Hamilton County, Florida.

There were 5,596 housing units at an average density of 10.9 per square mile (4.2/km2).

29.3% of households consisted of individuals and 14.7% had someone living alone who was 65 years of age or older.

[16] The 2016-2020 5-year American Community Survey estimates show that the median household income was $38,300 (with a margin of error of +/- $6,178).

[24][25] As of the census[26] of 2000, there were 13,327 people, 4,161 households, and 2,995 families residing in the county.

24.10% of all households were made up of individuals, and 9.10% had someone living alone who was 65 years of age or older.