Stephens County was created at statehood from portions of both Oklahoma Territory and Indian Territory. About two-thirds of the area came from Pickens County, Chickasaw Nation, in the Indian Territory, and the western third came from Comanche County, Oklahoma Territory. The town of Duncan was designated as the county seat. County offices were located in rented facilities in Duncan until the first courthouse was built in 1921. That building was replaced by a new facility in 1967. Drilling for oil and gas began about 1910. The first production well did not come in until 1918. Production support activities soon followed. Erle P. Halliburton founded the Halliburton Oil Well Cementing Company in Duncan. The company has since grown into a multinational corporation with headquarters in Dubai and Houston, Texas.
Geography
According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. It lies within the Red Bed plains. Although there is no major river in the county, there are some creeks that provide drainage. Wildhorse Creek in the eastern part flows into the Washita River. Beaver Creek in the western part of the county flows into the Red River. Lakes in the county include Lake Humphreys, Clear Creek Lake, Duncan Lake, Comanche Lake, and Waurika Lake.
As of the census of 2000, there were 43,182 people, 17,463 households, and 12,590 families residing in the county. The population density was 19/km². There were 19,854 housing units at an average density of 9/km². The racial makeup of the county was 88.37% White, 2.20% Black or African American, 4.92% Native American, 0.30% Asian, 0.03% Pacific Islander, 1.44% from other races, and 2.74% from two or more races. 3.96% of the population were Hispanic or Latino of any race. There were 17,463 households out of which 30.40% had children under the age of 18 living with them, 59.50% were married couplesliving together, 9.20% had a female householder with no husband present, and 27.90% were non-families. 25.30% of all households were made up of individuals and 12.80% had someone living alone who was 65 years of age or older. The average household size was 2.44 and the average family size was 2.91. In the county, the population was spread out with 24.60% under the age of 18, 7.80% from 18 to 24, 25.10% from 25 to 44, 24.00% from 45 to 64, and 18.50% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 93.70 males. For every 100 females age 18 and over, there were 89.70 males. The median income for a household in the county was $30,709, and the median income for a family was $36,371. Males had a median income of $30,428 versus $20,055 for females. The per capita income for the county was $16,357. About 11.60% of families and 14.60% of the population were below the poverty line, including 19.50% of those under age 18 and 11.90% of those age 65 or over.
