Sebastian County is a county located in the U.S. state of Arkansas. As of the 2020 census, the population was 127,799, making it the fourth-most populous county in Arkansas. The county has two county seats, Greenwood and Fort Smith.

Sebastian County is part of the Fort Smith, AR-OK Metropolitan Statistical Area.

Sebastian County is Arkansas's 56th county, formed on January 6, 1851, and named for William K. Sebastian, United States Senator from Arkansas.

According to the U.S. Census Bureau, the county has a total area of 546 square miles (1,410 km), of which 532 square miles (1,380 km) is land and 14 square miles (36 km) (2.6%) is water. It is the second-smallest county by area in Arkansas.

• Crawford County (north)
• Franklin County (east)
• Logan County (southeast)
• Scott County (south)
• Le Flore County, Oklahoma (southwest)
• Sequoyah County, Oklahoma (northwest)

• Fort Smith National Historic Site (part)
• Ouachita National Forest (part)

Historical population

Census	Pop.	Note	%±
1860	9,238		—
1870	12,940		40.1%
1880	19,560		51.2%
1890	33,200		69.7%
1900	36,935		11.3%
1910	52,278		41.5%
1920	56,739		8.5%
1930	54,426		−4.1%
1940	62,809		15.4%
1950	64,202		2.2%
1960	66,685		3.9%
1970	79,237		18.8%
1980	95,172		20.1%
1990	99,590		4.6%
2000	115,071		15.5%
2010	125,744		9.3%
2020	127,799		1.6%
2023 (est.)	129,098		1.0%
U.S. Decennial Census 1790–1960 1900–1990 1990–2000 2010

Sebastian County racial composition

Race	Number	Percentage
White (non-Hispanic)	82,785	64.78%
Black or African American (non-Hispanic)	7,891	6.17%
Native American	2,379	1.86%
Asian	5,700	4.46%
Pacific Islander	91	0.07%
Other/Mixed	9,625	7.53%
Hispanic or Latino	19,328	15.12%

As of the 2020 United States census, there were 127,799 people, 51,384 households, and 32,517 families residing in the county.

As of the 2000 United States census, there were 115,071 people, 45,300 households, and 30,713 families residing in the county. The population density was 215 inhabitants per square mile (83/km). There were 49,311 housing units at an average density of 92 per square mile (36/km). The racial makeup of the county was 82.34% White, 6.16% Black or African American, 1.57% Native American, 3.51% Asian, 0.05% Pacific Islander, 3.71% from other races, and 2.67% from two or more races. 6.70% of the population were Hispanic or Latino of any race. 19.6% were of American, 12.6% German, 11.0% Irish and 9.0% English ancestry according to Census 2000. 5.49% reported speaking Spanish at home, while 1.47% speak Vietnamese and 0.97% Lao.

In 2000 there were 45,300 households, out of which 32.80% had children under the age of 18 living with them, 52.40% were married couples living together, 11.30% had a female householder with no husband present, and 32.20% were non-families. 27.50% 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 2.49 and the average family size was 3.04.

In the county, the population was spread out, with 26.00% under the age of 18, 9.20% from 18 to 24, 29.50% from 25 to 44, 22.30% from 45 to 64, and 13.00% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 95.30 males. For every 100 females age 18 and over, there were 92.10 males.

The median income for a household in the county was $33,889, and the median income for a family was $41,303. Males had a median income of $30,056 versus $22,191 for females. The per capita income for the county was $18,424. About 10.40% of families and 13.60% of the population were below the poverty line, including 18.60% of those under age 18 and 10.00% of those age 65 or over.

As of 2010 census the population of Sebastian County was 125,744. The racial makeup of the county was 72.83% Non-Hispanic white, 6.24% Non-Hispanic black, 1.88% Native American, 4.06% Asian, 0.09% Pacific Islander, 0.07% Non-Hispanics of some other race, 2.78% Non-Hispanics reporting two or more races and 12.82% Hispanics.

Politics

Whereas most of Arkansas was overwhelmingly blue up to the mid-2000s, Sebastian has been a solidly Republican county at the presidential level since Dwight Eisenhower won it in 1952. Since that election, no Democrat has ever again carried this county, though native son Bill Clinton came within less than 1,000 votes of doing so during both of his campaigns. Jimmy Carter is the only other Democrat to come reasonably close to winning the county. However, Democrats continued to split most local offices and state legislative seats with Republicans well into the 1990s. While Fort Smith has elected Democratic mayors and still elects some Democrats to the state legislature, the rest of the county is powerfully Republican.

United States presidential election results for Sebastian County, Arkansas

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	30,719	67.59%	13,652	30.04%	1,081	2.38%
2020	31,198	66.18%	14,487	30.73%	1,455	3.09%
2016	29,127	65.25%	12,300	27.56%	3,210	7.19%
2012	29,169	67.27%	13,092	30.19%	1,101	2.54%
2008	28,637	66.27%	13,673	31.64%	902	2.09%
2004	27,303	61.76%	16,479	37.27%	429	0.97%
2000	23,483	58.48%	15,555	38.73%	1,121	2.79%
1996	16,482	46.63%	15,514	43.89%	3,350	9.48%
1992	16,817	42.40%	16,570	41.78%	6,272	15.81%
1988	24,426	70.94%	9,684	28.13%	322	0.94%
1984	27,595	74.95%	8,688	23.60%	534	1.45%
1980	23,403	63.46%	10,141	27.50%	3,335	9.04%
1976	17,671	52.79%	15,768	47.11%	34	0.10%
1972	25,219	81.23%	5,770	18.58%	58	0.19%
1968	12,073	44.65%	6,320	23.37%	8,649	31.98%
1964	13,110	55.80%	10,299	43.84%	84	0.36%
1960	11,744	56.75%	8,726	42.16%	226	1.09%
1956	10,234	57.36%	7,489	41.98%	118	0.66%
1952	10,114	56.36%	7,802	43.48%	28	0.16%
1948	2,928	33.09%	5,075	57.36%	845	9.55%
1944	3,452	36.46%	6,008	63.46%	7	0.07%
1940	1,968	27.16%	5,249	72.44%	29	0.40%
1936	1,161	20.30%	4,539	79.35%	20	0.35%
1932	1,268	20.26%	4,937	78.87%	55	0.88%
1928	3,465	51.84%	3,186	47.67%	33	0.49%
1924	1,985	33.13%	3,148	52.54%	859	14.34%
1920	3,492	46.03%	3,852	50.78%	242	3.19%
1916	1,366	26.86%	3,719	73.14%	0	0.00%
1912	514	12.53%	2,396	58.40%	1,193	29.08%
1908	2,050	35.73%	3,035	52.90%	652	11.36%
1904	1,254	38.16%	1,645	50.06%	387	11.78%
1900	964	31.21%	2,094	67.79%	31	1.00%
1896	1,009	27.57%	2,622	71.64%	29	0.79%
1892	1,558	34.71%	2,692	59.97%	239	5.32%

Public education is provided by several school districts (listed below from largest to smallest):

• Fort Smith School District
• Greenwood School District
• Lavaca School District
• Hackett School District
• Hartford School District

• Central City
• Midland

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 Sebastian County are listed below; listed in parentheses are the cities, towns, and/or census-designated places that are fully or partially inside the township.

• John Sebastian Little, member of the United States House of Representatives and the 21st Governor of the U.S. state of Arkansas
• Mathew Pitsch, Republican member of the Arkansas House of Representatives for Sebastian County

• List of lakes in Sebastian County, Arkansas
• National Register of Historic Places listings in Sebastian County, Arkansas

• Sebastian County, Arkansas entry on the Encyclopedia of Arkansas History & Culture
• Sebastian County official website

35°35′39″N 94°15′29″W / 35.59417°N 94.25806°W / 35.59417; -94.25806