Adjacent counties

• Bolivar County (north)
• Sunflower County (northeast)
• Humphreys County (east)
• Sharkey County (southeast)
• Issaquena County (south)
• Chicot County, Arkansas (west)
• Desha County, Arkansas (northwest)

National protected areas

• Holt Collier National Wildlife Refuge
• Theodore Roosevelt National Wildlife Refuge (part)
• Yazoo National Wildlife Refuge

2020 census

As of the 2020 United States Census, there were 44,922 people, 17,988 households, and 11,232 families residing in the county.

2010 census

As of the 2010 United States Census, there were 51,137 people living in the county. 71.3% were Black or African American, 27.0% White, 0.6% Asian, 0.1% Native American, 0.4% of some other race and 0.6% of two or more races. 1.0% were Hispanic or Latino (of any race).

2000 census

As of the census^[13] of 2000, there were 62,977 people, 22,158 households, and 15,931 families living in the county. The population density was 87 people per square mile (34 people/km²). There were 24,381 housing units at an average density of 34 units per square mile (13 units/km²). The racial makeup of the county was 69.57% Black or African American, 33.97% White, 0.09% Native American, 0.53% Asian, 0.02% Pacific Islander, 0.25% from other races, and 0.57% from two or more races. 0.84% of the population were Hispanic or Latino of any race.

According to the census^[13] of 2000, the largest ancestry groups in Washington County were African 69.57%, English 21.4%, Scottish 8.2% and Scots-Irish 3.1%

Washington County by 2005 was 67.2% African-American in population. Latinos constituted 1.1% of the population in the county while non-Hispanic whites made up 31.7% of the population.

As of the census^[13] of 2000, there were 22,158 households, out of which 36.30% had children under the age of 18 living with them, 40.60% were married couples living together, 26.00% had a female householder with no husband present, and 28.10% were non-families. 24.60% of all households were made up of individuals, and 10.00% had someone living alone who was 65 years of age or older. The average household size was 2.80 and the average family size was 3.35.

In the county, the population was spread out, with 31.50% under the age of 18, 10.10% from 18 to 24, 26.50% from 25 to 44, 20.50% from 45 to 64, and 11.50% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 87.70 males. For every 100 females age 18 and over, there were 80.30 males.

The median income for a household in the county was $25,757, and the median income for a family was $30,324. Males had a median income of $28,266 versus $20,223 for females. The per capita income for the county was $13,430. About 24.90% of families and 29.20% of the population were below the poverty line, including 38.40% of those under age 18 and 24.60% of those age 65 or over.

Washington County's demographics are rooted in the region's mid-nineteenth-century ascendance in cotton production and, accordingly, importation of people as slaves. According to the historian Sven Beckert, the county had "more than ten slaves for every white inhabitant" in 1840, and "every white family in the county held on average more than eighty slaves" by 1850.^[14]

1990 census

As of the census of 1990, there were 67,935 people living in the county. The racial makeup of the county was 57.46% (39,035) Black or African American, 41.47% (28,174) White, 0.08% (53) Native American, 0.36% (244) Asian, and 0.02% (13) from other races. 0.61% (416) were Hispanic or Latino of any race.

Major highways

• U.S. Highway 82
• U.S. Highway 61
• U.S. Highway 278
• Mississippi Highway 1
• Mississippi Highway 12

Airport

Mid Delta Regional Airport, owned by the City of Greenville, is located in an unincorporated area in the county.^[15]

Cities

• Greenville (third and current county seat)
• Hollandale
• Leland

Towns

• Arcola
• Metcalfe

Census-designated places

• Elizabeth
• Glen Allan
• Stoneville
• Winterville

Unincorporated communities

Ghost towns

• New Mexico (first county seat)
• Port Anderson
• Princeton (second county seat)