|Union County, Florida|
Location in the U.S. state of Florida
Florida's location in the U.S.
|Founded||May 20, 1921|
|Largest city||Lake Butler|
|• Total||250 sq mi (647 km2)|
|• Land||244 sq mi (632 km2)|
|• Water||6.2 sq mi (16 km2), 2.5%|
|• ( 2015)||15,234|
|• Density||64/sq mi (25/km2)|
|Time zone||Eastern: UTC−5/ −4|
Union County is a county in the U.S. state of Florida, the smallest in the state. As of the 2010 census, the population was 15,535.  The county seat is Lake Butler.  With a per capita income of $18,255 (as of 2017), it is the third-poorest county in the United States. 
Union County was created in 1921 from part of Bradford County. It was named to honor the concept of unity. Union County is the location of Union Correctional Institution and the Reception and Medical Center (RMC).  Union CI is a maximum security prison and is home to part of Florida's Death Row. The death chamber is located at nearby Florida State Prison (FSP). Florida State Prison also houses some death-row inmates.
According to the U.S. Census Bureau, the county has an area of 250 square miles (650 km2), of which 244 square miles (630 km2) is land and 6.2 square miles (16 km2) (2.5%) is water.  It is the smallest county by area in Florida.
- Bradford County, Florida – southeast
- Alachua County, Florida – south
- Columbia County, Florida – west
- Baker County, Florida – north
|U.S. Decennial Census
1790-1960  1900-1990 
1990-2000  2010-2015 
At the 2000 census,  there were 13,442 people, 3,367 households and 2,606 families residing in the county. The population density was 56 per square mile (22/km²). There were 3,736 housing units at an average density of 16 per square mile (6/km²). The racial makeup of the county was 73.62% White, 22.84% Black or African American, 0.66% Native American, 0.31% Asian, 0.02% Pacific Islander, 1.04% from other races, and 1.50% from two or more races. 3.55% of the population were Hispanic or Latino of any race.
Of the 3,367 households, 41.80% had children under the age of 18 living with them, 57.70% were married couples living together, 15.00% had a female householder with no husband present, and 22.60% were non-families. 19.50% of all households were made up of individuals and 7.10% had someone living alone who was 65 years of age or older. The average household size was 2.76 and the average family size was 3.13.
The age distribution was 21.80% under the age of 18, 8.70% from 18 to 24, 39.80% from 25 to 44, 22.20% from 45 to 64, and 7.50% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 183.00 males. For every 100 females age 18 and over, there were 215.20 males. This extremely skewed gender distribution is the result of the county's male prison population.
The median household income was $34,563, and the median family income was $37,516. Males had a median income of $28,571 versus $22,083 for females. The county's per capita income was $12,333. About 10.50% of families and 14.00% of the population were below the poverty line, including 14.60% of those under age 18 and 16.20% of those age 65 or over.
The Florida Department of Corrections (FDOC) operates Region II Correctional Facility Office in an unincorporated area in Union County.  FDOC also maintains the Union Correctional Institution in an unincorporated area in the county.  Union Correctional Institution houses one of two death rows for men in Florida. 
Union County School District serves the county.
The Union County Public Library serves the county. The branch is at 250 SE 5th Avenue, Lake Butler, Florida 32054. Its director is Mary C. Brown. The branch is open Monday, Wednesday–Friday 9 am–6 pm, Tuesday 9 am–8 pm, and Saturday 9 am–3 pm.
- "State & County QuickFacts". United States Census Bureau. Retrieved February 15, 2014.
- "Find a County". National Association of Counties. Retrieved 2011-06-07.
- List of lowest-income counties in the United States
- "Reception and Medical Center (RMC)". Florida Department of Corrections. Retrieved July 28, 2010.
- "US Gazetteer files: 2010, 2000, and 1990". United States Census Bureau. 2011-02-12. Retrieved 2011-04-23.
- "Population and Housing Unit Estimates". Retrieved June 9, 2017.
- "U.S. Decennial Census". United States Census Bureau. Retrieved June 16, 2014.
- "Historical Census Browser". University of Virginia Library. Retrieved June 16, 2014.
- "Population of Counties by Decennial Census: 1900 to 1990". United States Census Bureau. Retrieved June 16, 2014.
- "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000" (PDF). United States Census Bureau. Retrieved June 16, 2014.
- "American FactFinder". United States Census Bureau. Retrieved 2011-05-14.
- " Region II Correctional Facility Office." Florida Department of Corrections. Retrieved on January 8, 2010.
- " Union Correctional Facility." Florida Department of Corrections. Retrieved on August 31, 2010.
- " Death Row Fact Sheet." Florida Department of Corrections. Retrieved on August 15, 2010.
- "Union Juvenile Residential Facility". Florida Department of Juvenile Justice. Retrieved 2008-08-03.
- Leip, David. "Dave Leip's Atlas of U.S. Presidential Elections". uselectionatlas.org. Retrieved 2018-06-16.
|Wikimedia Commons has media related to Union County, Florida.|
- Union County Times newspaper that serves Union County, Florida available in full-text with images in Florida Digital Newspaper Library
- Union County Public Library - Website for Union County's library with links to government services and the tri-county area's library catalog.
- Lake Butler Community Page a non-official 'Community Page' created by a local resident to help share information about events and more occurring in the Union County/Lake Butler area.
- Union County Board of County Commissioners
- Union County Supervisor of Elections
- Union County Property Appraiser
- Union County Sheriff's Office
- Union County Tax Collector
- Union County School Board
- Suwannee River Water Management District[ permanent dead link] [Dead link 26 August 2016]
- Union County Clerk of Courts
- Office of the State Attorney, 8th Judicial Circuit of Florida serving Alachua, Baker, Bradford, Gilchrist, Levy and Union Counties
- Circuit and County Court for the 8th Judicial Circuit of Florida