The county was formed on October 13, 1827, and named for the St. Francis River.
- Cross County (north)
- Crittenden County (east)
- Lee County (south)
- Monroe County (southwest)
- Woodruff County (northwest)
|U.S. Decennial Census|
As of the 2010 census, there were 28,258 people living in the county. 51.9% were Black or African American, 44.2% White, 0.5% Native American, 0.5% Asian, 1.4% of some other race and 1.5% of two or more races. 4.1% were Hispanic or Latino (of any race).
As of the 2000 census, there were 29,329 people, 10,043 households, and 7,230 families living in the county. The population density was 18/km² (46/mi²). There were 11,242 housing units at an average density of 7/km² (18/mi²). The racial makeup of the county was 48.36% White, 49.01% Black or African American, 0.25% Native American, 0.56% Asian, 0.02% Pacific Islander, 0.40% from other races, and 1.40% from two or more races. 4.88% of the population were Hispanic or Latino of any race.
There were 10,043 households out of which 35.30% had children under the age of 18 living with them, 46.90% were married couples living together, 20.80% had a female householder with no husband present, and 28.00% were non-families. 25.10% of all households were made up of individuals and 10.80% had someone living alone who was 65 years of age or older. The average household size was 2.65 and the average family size was 3.17.
In the county, the population was spread out with 27.90% under the age of 18, 9.90% from 18 to 24, 29.10% from 25 to 44, 21.20% from 45 to 64, and 11.90% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 105.60 males. For every 100 females age 18 and over, there were 105.40 males.
The median income for a household in the county was $26,146, and the median income for a family was $30,324. Males had a median income of $28,389 versus $20,578 for females. The per capita income for the county was $12,483. About 23.10% of families and 27.50% of the population were below the poverty line, including 38.70% of those under age 18 and 23.10% of those age 65 or over.
Government and infrastructure
In presidential elections, St. Francis County generally votes Democratic. It has voted Democratic in every election since 1912, other than 1968, 1972, and 1984.
Townships in Arkansas are the divisions of a county. Each township includes unincorporated areas; some may have incorporated cities or towns within part of their boundaries. Arkansas townships have limited purposes in modern times. However, the United States Census does list Arkansas population based on townships (sometimes referred to as "county subdivisions" or "minor civil divisions"). Townships are also of value for historical purposes in terms of genealogical research. Each town or city is within one or more townships in an Arkansas county based on census maps and publications. The townships of St. Francis County are listed below; listed in parentheses are the cities, towns, and/or census-designated places that are fully or partially inside the township. 
- Al Green, American singer, was born in Forrest City, St. Francis County.
- Charlie Rich, American country singer, was born in Colt, in St. Francis County.
- Sonny Liston, World heavyweight boxing champion, was born in Johnson Township, St. Francis County.
- Mark R. Martin, current Secretary of State of Arkansas, was raised near Blackfish Lake and graduated from Hughes High School in 1986.
- List of lakes in St. Francis County, Arkansas
- National Register of Historic Places listings in St. Francis County, Arkansas
- "State & County QuickFacts". United States Census Bureau. Retrieved May 19, 2014.
- "Find a County". National Association of Counties. Retrieved 2011-06-07.
- "2010 Census Gazetteer Files". United States Census Bureau. August 22, 2012. Retrieved August 27, 2015.
- "Population and Housing Unit Estimates". Retrieved September 28, 2019.
- "U.S. Decennial Census". United States Census Bureau. Retrieved August 27, 2015.
- "Historical Census Browser". University of Virginia Library. Retrieved August 27, 2015.
- Forstall, Richard L., ed. (March 27, 1995). "Population of Counties by Decennial Census: 1900 to 1990". United States Census Bureau. Retrieved August 27, 2015.
- "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000" (PDF). United States Census Bureau. April 2, 2001. Retrieved August 27, 2015.
- Based on 2000 census data
- "U.S. Census website". United States Census Bureau. Retrieved 2011-05-14.
- "Forrest City city, Arkansas[permanent dead link]." U.S. Census Bureau. Retrieved on May 1, 2011.
- "FCI Forrest City Medium Contact Information." Federal Bureau of Prisons. Retrieved on May 1, 2011. "FCI FORREST CITY MEDIUM FEDERAL CORRECTIONAL INSTITUTION 1400 DALE BUMPERS ROAD FORREST CITY, AR 72335"
- "Dave Leip's Atlas of U.S. Presidential Elections". Retrieved November 18, 2016.
- 2011 Boundary and Annexation Survey (BAS): St. Francis County, AR (PDF) (Map). U. S. Census Bureau. Archived from the original (PDF) on 2012-10-19. Retrieved 2011-08-06.
- "Arkansas: 2010 Census Block Maps - County Subdivision". United States Census Bureau. Retrieved May 29, 2014.
- St. Francis county official website
- St. Francis, Arkansas entry on the Encyclopedia of Arkansas History & Culture