Stephens County is a county located in the U.S. state of Oklahoma. As of the 2020 census, its population was 42,848. Its county seat is Duncan. The county was created at statehood, partly from the Chickasaw Nation in Indian Territory and partly from Comanche County in Oklahoma Territory. It was named for Texas politician John Hall Stephens.

Stephens County comprises the Duncan, OK micropolitan statistical area.

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.

According to the U.S. Census Bureau, the county has a total area of 891 square miles (2,310 km), of which 21 square miles (54 km) (2.4%) are covered by water. It lies within the Red Bed plains. Although no major river is in the county, some creeks 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.

• Grady County (north)
• Garvin County (northeast)
• Carter County (southeast)
• Jefferson County (south)
• Cotton County (southwest)
• Comanche County (northwest)

Historical population

Census	Pop.	Note	%±
1910	22,252		—
1920	24,692		11.0%
1930	33,069		33.9%
1940	31,090		−6.0%
1950	34,071		9.6%
1960	37,990		11.5%
1970	35,902		−5.5%
1980	43,419		20.9%
1990	42,299		−2.6%
2000	43,182		2.1%
2010	45,048		4.3%
2020	42,848		−4.9%
U.S. Decennial Census 1790-1960 1900-1990 1990-2000 2010

As of the census of 2000, 43,182 people, 17,463 households, and 12,590 families wereresiding in the county. The population density was 19/km (49/sq mi). There were 19,854 housing units at an average density of 9/km (23/sq mi). 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. According to the 2020 census, its population was 42,848.

In 2000, there were 17,463 households, out of which 30.40% had children under the age of 18 living with them, 59.50% were married couples living 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.

In 2000, 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. According to 2017-2021 census estimates, its median household income was $53,470 with a poverty rate of 18.9%.

Voter Registration and Party Enrollment as of June 30, 2023
Party		Number of Voters	Percentage
	Democratic	5,854	21.71%
	Republican	16,996	63.04%
	Others	4,112	15.25%
Total		26,962	100%

United States presidential election results for Stephens County, Oklahoma

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2020	15,560	81.65%	3,154	16.55%	343	1.80%
2016	14,182	79.21%	3,086	17.24%	636	3.55%
2012	12,908	76.62%	3,939	23.38%	0	0.00%
2008	14,394	76.03%	4,538	23.97%	0	0.00%
2004	13,646	71.22%	5,515	28.78%	0	0.00%
2000	10,860	62.10%	6,467	36.98%	161	0.92%
1996	8,144	45.81%	7,248	40.77%	2,384	13.41%
1992	7,085	34.61%	7,644	37.34%	5,742	28.05%
1988	9,844	55.32%	7,833	44.02%	118	0.66%
1984	12,871	66.58%	6,359	32.89%	103	0.53%
1980	10,199	57.13%	7,191	40.28%	462	2.59%
1976	7,099	41.71%	9,795	57.55%	126	0.74%
1972	10,309	71.61%	3,623	25.17%	464	3.22%
1968	5,508	38.46%	5,249	36.65%	3,566	24.90%
1964	5,323	36.47%	9,272	63.53%	0	0.00%
1960	8,084	53.95%	6,899	46.05%	0	0.00%
1956	6,324	45.67%	7,524	54.33%	0	0.00%
1952	6,461	44.59%	8,029	55.41%	0	0.00%
1948	1,909	22.17%	6,702	77.83%	0	0.00%
1944	2,766	30.82%	6,189	68.97%	19	0.21%
1940	2,989	32.59%	6,149	67.04%	34	0.37%
1936	1,636	20.27%	6,390	79.17%	45	0.56%
1932	1,012	11.61%	7,706	88.39%	0	0.00%
1928	5,192	62.71%	2,982	36.02%	105	1.27%
1924	2,377	31.55%	4,745	62.98%	412	5.47%
1920	2,035	39.16%	2,816	54.19%	346	6.66%
1916	607	15.00%	2,343	57.88%	1,098	27.12%
1912	598	18.41%	1,735	53.42%	915	28.17%

• Comanche
• Duncan (county seat)
• Marlow

• Bray
• Central High
• Empire City
• Velma

• Loco

• Meridian (former)
• Sunray

• Alma
• Corum
• Santa Fe

• National Register of Historic Places listings in Stephens County, Oklahoma

34°29′N 97°52′W / 34.48°N 97.86°W / 34.48; -97.86