Adjacent counties

• Carroll County (north)
• Newton County (east)
• Johnson County (southeast)
• Franklin County (south)
• Crawford County (southwest)
• Washington County (west)
• Benton County (northwest)

National protected area

• Ozark National Forest (part)

2020 census

As of the 2020 United States census, there were 16,521 people, 6,279 households, and 4,318 families residing in the county.

2000 census

As of the 2000 census,^[13] there were 14,243 people, 5,463 households, and 4,080 families residing in the county. The population density was 7/km² (18/sq mi). There were 6,537 housing units at an average density of 3/km² (7.8/sq mi). The racial makeup of the county was 95.94% White, 0.11% Black or African American, 1.22% Native American, 0.06% Asian, 0.09% Pacific Islander, 1.47% from other races, and 1.10% from two or more races. 3.06% of the population were Hispanic or Latino of any race.

There were 5,463 households, out of which 33.90% had children under the age of 18 living with them, 63.00% were married couples living together, 7.90% had a female householder with no husband present, and 25.30% were non-families. 22.40% of all households were made up of individuals, and 10.40% had someone living alone who was 65 years of age or older. The average household size was 2.59 and the average family size was 3.03.

In the county, the population was spread out, with 26.80% under the age of 18, 7.50% from 18 to 24, 27.00% from 25 to 44, 24.30% from 45 to 64, and 14.40% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 99.70 males. For every 100 females age 18 and over, there were 97.30 males.

The median income for a household in the county was $27,895, and the median income for a family was $32,910. Males had a median income of $24,911 versus $18,786 for females. The per capita income for the county was $14,736. About 14.70% of families and 18.60% of the population were below the poverty line, including 24.60% of those under age 18 and 18.00% of those age 65 or over.

Major highways

• U.S. Highway 412
• Highway 12
• Highway 16
• Highway 21
• Highway 23
• Highway 45
• Highway 74

Airport

The Huntsville Municipal Airport is a public-use airport located two nautical miles (4 km) southwest of the central business district of Huntsville.^[16]

City

• Huntsville (county seat)

Towns

• Hindsville
• St. Paul

Unincorporated communities

Townships

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 Madison County are listed below; listed in parentheses are the cities, towns, and/or census-designated places that are fully or partially inside the township. ^[17][18]