19th century

Settlers in the 19th century found earthwork mounds, 10 to 15 feet in height, in areas around what developed as Arkadelphia, Arkansas. Some were excavated for pottery and other grave goods.^[4]

At the time of European-American settlement after the United States acquired this territory in the Louisiana Purchase of 1803, the pioneers encountered three major Native American tribes: the Caddo, who lived along the banks of the Caddo River; the Quapaw on the Ouachita River, for several miles below what is now Arkadelphia; and the Lenape (known then as Delaware, who were driven to this area by European pressure from the mid-Atlantic East Coast) along the lower Ouachita to below present-day Camden. (This site had been named as Écore à Fabre, after a colonial French trader Fabre.)^[4]

Clark County was the third county formed by Americans in Arkansas, on December 15, 1818, together with Hempstead and Pulaski counties. The county is named after William Clark, then Governor of the Missouri Territory, which included present-day Arkansas. On November 1, 1833, the Arkansas territorial legislature created Pike County from western Clark County and part of northern Hempstead County. It was named after US explorer Zebulon Pike.

Arkadelphia was designated as the county seat in 1842. It became increasingly important as a hub after railroads were constructed to here that connected with numerous markets. Timber harvesting became important by the end of the century. By 1890, forest products were ranked next to agriculture in economic importance. In the 20th century, continued modern technological developments established the industry's continued importance in the county's economy.

Three of the six lynchings recorded in Clark County from 1877 to 1950^[5] took place in a mass event in late January 1879. An African-American man, Ben Daniels, and three of his four sons (ranging in age from 22 to 18) were arrested as suspects in an alleged robbery and assault of a white man and held in the county jail. Daniels and two of his sons were forcibly taken out of the jail by a white mob and lynched by hanging from trees in the courthouse square, without trial. One son, believed to be Charles Daniels (22), survived for trial. He was convicted and served in prison until about 1886 or 1887.^[6]

Major highways

• Interstate 30
• U.S. Highway 67
• Highway 7
• Highway 8
• Highway 26
• Highway 51
• Highway 53

Adjacent counties

• Hot Spring County (northeast)
• Dallas County (east)
• Ouachita County (southeast)
• Nevada County (southwest)
• Pike County (west)
• Montgomery County (northwest)

2020 census

As of the 2020 United States census, there were 21,446 people, 8,446 households, and 5,253 families residing in the county.

2000 census

As of the 2000 census,^[16] there were 23,546 people, 8,912 households, and 5,819 families residing in the county. The population density was 27 people per square mile (10 people/km²). There were 10,166 housing units at an average density of 12 units per square mile (4.6 units/km²). The racial makeup of the county was 74.28% White, 22.02% Black or African American, 0.46% Native American, 0.62% Asian, 0.04% Pacific Islander, 1.37% from other races, and 1.20% from two or more races. 2.40% of the population were Hispanic or Latino of any race.

There were 8,912 households, out of which 29.80% had children under the age of 18 living with them, 49.80% were married couples living together, 12.20% had a female householder with no husband present, and 34.70% were non-families. 27.60% of all households were made up of individuals, and 12.40% had someone living alone who was 65 years of age or older. The average household size was 2.38 and the average family size was 2.91.

In the county, the population was spread out, with 21.70% under the age of 18, 20.00% from 18 to 24, 23.80% from 25 to 44, 19.90% from 45 to 64, and 14.60% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 92.70 males. For every 100 females age 18 and over, there were 88.90 males.

The median income for a household in the county was $28,845, and the median income for a family was $37,092. Males had a median income of $28,692 versus $19,886 for females. The per capita income for the county was $14,533. About 13.50% of families and 19.10% of the population were below the poverty line, including 20.90% of those under age 18 and 18.40% of those age 65 or over.

County Officials

Republicans hold every county-wide office except the Sheriff and Collector, and have a seven-to-four super-majority on the Quorum Court. Most positions regularly go unopposed with only one candidate making the general election ballot.^[22][23][24] Democrats picked up one seat in 2022 by flipping District 2.^[25]

Incorporated cities

• Amity
• Arkadelphia (county seat)
• Caddo Valley
• Gurdon

Incorporated towns

• Gum Springs
• Okolona
• Whelen Springs

Census-designated places

• Alpine
• Beirne

Other unincorporated communities

• Barringer^[27]
• Boswell^[28]
• Burtsell^[29]
• Curtis^[30]
• Fendley^[31]
• Hollywood^[32]
• Joan^[33]
• Kansas^[34]
• Vaden^[35]

Ghost towns and former communities

• Clear Spring^[36]
• Graysonia
• Greenville (former county seat)^[37]
• Halfway^[38]
• Lenox^[39]
• Rome^[40]

Townships

Note: Unlike most Arkansas counties, Clark County has only one township. That township encompasses the entire county.

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 Clark County are listed below; listed in parentheses are the cities, towns, and/or census-designated places that are fully or partially inside the township. ^[41][42]

• Caddo