Sioux County is a county in the U.S. state of Nebraska. As of the 2020 United States Census, the population was 1,135. Its county seat is Harrison.

Sioux County is included in the Scottsbluff, NE Micropolitan Statistical Area.

In the Nebraska license plate system, Sioux County is represented by the prefix 80 (it had the 80th-largest number of vehicles registered in the state when the license plate system was established in 1922).

Sioux County lies at the NW corner of Nebraska. Its north boundary line abuts the south line of the state of South Dakota and its west boundary line abuts the east boundary line of the state of Wyoming. The Niobrara River flows southeastward and eastward through the upper central part of the county. The county terrain is arid low rolling hills, sloping to the east and southeast. The terrain is sparsely utilized for agriculture, with some center pivot irrigation used. The county has an area of 2,067 square miles (5,350 km), of which 2,067 square miles (5,350 km) is land and 0.7 square miles (1.8 km) (0.03%) is water.

Historical population

Census	Pop.	Note	%±
1880	699		—
1890	2,452		250.8%
1900	2,055		−16.2%
1910	5,599		172.5%
1920	4,528		−19.1%
1930	4,667		3.1%
1940	4,001		−14.3%
1950	3,124		−21.9%
1960	2,575		−17.6%
1970	2,034		−21.0%
1980	1,845		−9.3%
1990	1,549		−16.0%
2000	1,475		−4.8%
2010	1,311		−11.1%
2020	1,135		−13.4%
2022 (est.)	1,127		−0.7%
US Decennial Census 1790-1960 1900-1990 1990-2000 2010 2020 2022

As of the 2020 United States Census, there were 1,135 people and 450 households in the county. The population density was 0.56 person per square mile (0.22 person/km). There were 715 housing units at an average density of 0.34 units per square mile (0.13/km). The racial makeup of the county was 95.2% White, 1.5% Native American, 0.4% Asian, and 2.4% from two or more races. 6.1% of the population were Hispanic or Latino of any race.

The county population contained 21% under the age of 18, 47.3% from 18 to 64, and 31.7% who were 65 years of age or older. 46.7% of the population were female.

The median income for a household in the county in 2022 was $50,833. The per capita income for the county was $26,748. 16.1% of the population were below the poverty line.

As of the 2000 United States Census, there were 1,475 people, 605 households, and 444 families in the county. The population density was 0.7 person per square mile (0.27 person/km). There were 780 housing units at an average density of 0.4 units per square mile (0.15/km). The racial makeup of the county was 97.63% White, 0.14% Native American, 0.20% Asian, 1.15% from other races, and 0.88% from two or more races. 2.31% of the population were Hispanic or Latino of any race. 36.9% were of German, 11.3% Irish, 11.0% American and 10.6% English ancestry.

There were 605 households, out of which 28.10% had children under the age of 18 living with them, 65.30% were married couples living together, 5.10% had a female householder with no husband present, and 26.60% were non-families. 23.60% of all households were made up of individuals, and 9.40% 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 2.86.

The county population contained 24.30% under the age of 18, 7.20% from 18 to 24, 24.70% from 25 to 44, 27.50% from 45 to 64, and 16.20% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 111.00 males. For every 100 females age 18 and over, there were 102.20 males.

The median income for a household in the county was $29,851, and the median income for a family was $31,406. Males had a median income of $23,409 versus $21,490 for females. The per capita income for the county was $15,999. About 11.10% of families and 15.40% of the population were below the poverty line, including 24.40% of those under age 18 and 7.50% of those age 65 or over.

• Harrison (county seat)

• Agate
• Andrews
• Glen
• Joder
• Story

• Montrose
• Orella

Sioux County voters are reliably Republican. In no national election since 1936 has the county selected the Democratic Party candidate. In 2020, Donald Trump won the highest share of the vote ever in the county, with 87.8% of the vote.

United States presidential election results for Sioux County, Nebraska

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	597	87.79%	77	11.32%	6	0.88%
2020	642	87.82%	72	9.85%	17	2.33%
2016	616	83.70%	81	11.01%	39	5.30%
2012	624	84.44%	101	13.67%	14	1.89%
2008	603	82.38%	117	15.98%	12	1.64%
2004	677	83.68%	123	15.20%	9	1.11%
2000	629	83.64%	98	13.03%	25	3.32%
1996	551	71.74%	138	17.97%	79	10.29%
1992	445	55.49%	148	18.45%	209	26.06%
1988	568	74.05%	194	25.29%	5	0.65%
1984	732	85.12%	121	14.07%	7	0.81%
1980	760	81.55%	120	12.88%	52	5.58%
1976	532	60.25%	329	37.26%	22	2.49%
1972	639	83.20%	129	16.80%	0	0.00%
1968	565	71.43%	157	19.85%	69	8.72%
1964	698	64.81%	379	35.19%	0	0.00%
1960	745	64.22%	415	35.78%	0	0.00%
1956	499	65.74%	260	34.26%	0	0.00%
1952	1,093	78.46%	300	21.54%	0	0.00%
1948	657	55.82%	520	44.18%	0	0.00%
1944	876	68.22%	408	31.78%	0	0.00%
1940	1,072	63.43%	618	36.57%	0	0.00%
1936	674	40.65%	956	57.66%	28	1.69%
1932	667	39.14%	1,006	59.04%	31	1.82%
1928	1,178	72.54%	435	26.79%	11	0.68%
1924	480	36.01%	149	11.18%	704	52.81%
1920	627	64.97%	252	26.11%	86	8.91%
1916	344	30.50%	737	65.34%	47	4.17%
1912	150	15.14%	375	37.84%	466	47.02%
1908	516	50.84%	464	45.71%	35	3.45%
1904	247	62.06%	111	27.89%	40	10.05%
1900	199	44.42%	248	55.36%	1	0.22%

• National Register of Historic Places listings in Sioux County NE

• Sioux County website

42°29′N 103°46′W / 42.48°N 103.77°W / 42.48; -103.77