Chattahoochee County, also known as Cusseta-Chattahoochee County, is a county located on the western border in central Georgia. As of the 2020 census, the population was 9,565. The county seat is Cusseta, with which the county shares a consolidated city-county government. The city of Cusseta remains a geographically distinct municipality within Chattahoochee County. The county was created on February 13, 1854.
 Chattahoochee County is included in the Columbus, GA-AL Metropolitan Statistical Area.
 This area was occupied by the historic Muscogee people (also known as the Creek) at the time of European encounter. They had a large confederacy in the Southeast. They were among the Five Civilized Tribes who were forcibly removed to Indian Territory in the 1830s during the administration of President Andrew Jackson. European Americans moved into their former areas, in some cases acquiring land through lotteries run by the state.
 The Georgia General Assembly created Chattahoochee County on February 13, 1854, from portions of Muscogee and Marion counties. It is named for the Chattahoochee River that forms its western boundary. The county seat was named Cusseta to commemorate the historic Creek Indian town of that name that long existed nearby. In 2004–2005, the U.S. Census Bureau reported a 6.2% population decline, making this county at the top of those nationally with shrinking populations.
 The original courthouse, built in 1854 by enslaved African Americans, is preserved at the tourist attraction of Westville in Columbus, Georgia.
 Since 1918, most of the land in Chattahoochee County has been part of the Fort Moore military reservation.
 According to the U.S. Census Bureau, the county has a total area of 251 square miles (650 km2), of which 249 square miles (640 km2) is land and 2.4 square miles (6.2 km2) (1.0%) is water.
 The vast majority of Chattahoochee County is located in the Middle Chattahoochee River-Walter F. George Lake subbasin of the ACF River Basin (Apalachicola-Chattahoochee-Flint River Basin). The very small southeastern corner of the county is located in the Kinchafoonee-Muckalee subbasin of the same larger ACF Basin.
 The county population has declined by more than half since its peak in 1970. People have left for job opportunities elsewhere.

 As of the 2020 United States Census, there were 9,565 people, 2,570 households, and 1,886 families residing in the county.
 As of the 2010 United States Census, there were 11,267 people, 2,686 households, and 2,067 families residing in the county. The population density was 45.3 inhabitants per square mile (17.5/km2). There were 3,376 housing units at an average density of 13.6 per square mile (5.3/km2). The racial makeup of the county was 68.8% white, 18.8% black or African American, 2.2% Asian, 0.7% American Indian, 0.6% Pacific islander, 4.4% from other races, and 4.4% from two or more races. Those of Hispanic or Latino origin made up 12.4% of the population. In terms of ancestry, 17.5% were German, 14.9% were Irish, 10.1% were English, 6.8% were Italian, and 3.1% were American.
 Of the 2,686 households, 53.7% had children under the age of 18 living with them, 57.0% were married couples living together, 16.2% had a female householder with no husband present, 23.0% were non-families, and 19.1% of all households were made up of individuals. The average household size was 2.98 and the average family size was 3.45. The median age was 24.0 years.  Although its population has declined, the county was notable in 2016 for having the highest proportion of millennials (persons 15–34 years old) of any county within the United States: 59.7%.
 The median income for a household in the county was $51,089 and the median income for a family was $55,745. Males had a median income of $41,117 versus $31,422 for females. The per capita income for the county was $22,202. About 14.7% of families and 15.9% of the population were below the poverty line, including 18.4% of those under age 18 and 30.7% of those age 65 or over.
 
 The Chattahoochee County School District holds pre-school to grade twelve, and consists of one elementary school, a middle school, and a high school. The district has 85 full-time teachers and over 1000 students.
 All parts of the county except Fort Moore are zoned to county schools for all grades. Fort Moore children are zoned to Department of Defense Education Activity (DoDEA) schools for grades K-8. However Fort Moore high school students attend the public high schools in the respective counties they are located in.
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