# O'Brien County, Iowa

O'Brien County is a county in the U.S. state of Iowa. As of the 2020 United States census, the population was 14,182. The county seat is Primghar.

## History

By the time Iowa attained statehood (December 28, 1848), its Territorial Legislature had created 44 counties. On January 15, 1851, the new State Legislature created another 49 counties, defining them by lines of survey. O'Brien was among the 49 units thus created. It consists of four survey townships, each formed by 36 square miles arranged in a 6x6 layout, for a nominal 576 square miles total area. The county was named for William Smith O'Brien, a leader for Irish independence in 1848.
The new county's first settler arrived in 1856; Hannibal H. Waterman brought his wife and a daughter to the southeast portion (present Waterman Township). His homestead formed the nucleus of the county's first community, and a small building was erected there to function as a courthouse.
By 1872 the county comprised several small communities, and residents of those groups felt the county's business should be conducted in a more central location. An election was held, the outcome of which was to create a new county seat at its midpoint. A 40-acre (16-hectare) tract at the center of the county was surveyed and platted; its name (Primghar) was created from the initials of eight persons involved with the platting. The previous courthouse building was transported to this new location.
In 1874 a 35-foot square building was erected on the present location at a cost of $2,000, to replace the first structure. It was replaced in 1887 by a larger structure. The County Board of Supervisors authorized its construction, at a cost not to exceed $5,000 (the maximum amount the county was authorized to commit). To keep within this limit, members of the new community agreed to haul the building materials without charge from railroad stops at Sanborn and Paullina. The present courthouse was completed in 1917, and is listed on the National Register of Historic Places.

## Geography

According to the United States Census Bureau, the county has a total area of 573 square miles (1,480 km$^2$), of which 573 square miles (1,480 km$^2$) is land and 0.2 square miles (0.52 km$^2$) (0.03%) is water.

### Major highways

* U.S. Highway 18
* U.S. Highway 59
* Iowa Highway 10
* Iowa Highway 60
* Iowa Highway 143

### Adjacent counties

* Osceola County - north
* Clay County - east
* Cherokee County - south
* Sioux County - west

## Demographics
### 2020 census

The 2020 census recorded a population of 14,182 in the county, with a population density of 24.8184/sq mi (9.5824/km$^2$). 95.42% of the population reported being of one race. There were 6,524 housing units, of which 5,861 were occupied.
O'Brien County Racial Composition :
| Race | Num. | Perc. |
| White (NH) | 12,609 | 89% |
| Black or African American (NH) | 159 | 1.12% |
| Native American (NH) | 39 | 0.3% |
| Asian (NH) | 79 | 0.6% |
| Pacific Islander (NH) | 11 | 0.07% |
| Other/Mixed (NH) | 300 | 2.12% |
| Hispanic or Latino | 985 | 7% |

### 2010 census

As of the 2010 United States Census, there were 14,398 people, 6,069 households, and 3,927 families in the county. The population density was 25.1239/sq mi (9.7004/km$^2$). There were 6,649 housing units at an average density of 11 per square mile (4.2/km$^2$). The racial makeup of the county was 96.0% White, 0.5% Black or African American, 0.1% American Indian, 0.6% Asian, 2.0% from other races, and 0.8% from two or more races. The county has a 3.8% Hispanic or Latino background.
There were 6,069 households, out of which 26.0% had children under the age of 18 living with them, 55.1% were married couples living together, 6.1% had a female householder with no husband present, 3.5% had a male householder with no wife present, and 35.3% were non-families. 31.5% of all households were made up of individuals living alone, and 33.1% had someone living alone who was 65 years of age or older. The average household size was 2.31 and the average family size was 2.89.
The county population contained 25.7% under the age of 20, 4.6% from 20 to 24, 21.3% from 25 to 44, 28.1% from 45 to 64, and 20.4% who were 65 years of age or older. The median age was 43.6 years. For every 100 females there were 95.80 males. For every 100 females, there were 99.1 males.
The median income for a household in the county was $44,018, and the median income for a family was $58,127. The per capita income for the county was $24,771. About 6.3% of families and 11.0% of the population were below the poverty line, including 15.7% of those under age 18 and 8.3% of those age 65 or over.

## Communities
### Cities

* Archer
* Calumet
* Hartley
* Paullina
* Primghar
* Sanborn
* Sheldon
* Sutherland

### Unincorporated communities

* Gaza
* Germantown
* Moneta

### Townships

* Baker Township
* Caledonia Township
* Carroll Township
* Center Township
* Dale Township
* Floyd Township
* Franklin Township
* Grant Township
* Hartley Township
* Highland Township
* Liberty Township
* Lincoln Township
* Omega Township
* Summit Township
* Union Township
* Waterman Township

### Population ranking

The population ranking of the following table is based on the 2020 census of O'Brien County.
† county seat
| Rank | City/Town/etc. | Municipal type | Population (2020 Census) |
| 1 | Sheldon (partially in Sioux County) | City | 5,251 (5,512 total) |
| 2 | Hartley | City | 1,605 |
| 3 | Sanborn | City | 1,392 |
| 4 | Paullina | City | 982 |
| 5 | † Primghar | City | 896 |
| 6 | Sutherland | City | 629 |
| 7 | Calumet | City | 146 |
| 8 | Archer | City | 117 |

## Politics

O'Brien County is one of the most consistently Republican counties in Iowa. It has backed the Republican nominee in all but five elections in its history; its inaugural election in 1860, a tie in 1864, backing former Republican turned Progressive Theodore Roosevelt in 1912, and supporting Franklin D. Roosevelt during his two nationwide landslides in 1932 and 1936. Since 1952, the Republican candidate has carried O'Brien County by a margin of at least 20% in every election except for 1964, when Democrat Lyndon B. Johnson only lost the county by 41 votes amidst a nationwide Democratic landslide. In the 21st century, all Republican candidates have obtained over 65% of the county's vote, and beginning in 2012, at least 70% of the vote.
United States presidential election results for O'Brien County, Iowa :
| Year | Republican | Republican | Democratic | Democratic | Third party(ies) | Third party(ies) |
| Year | No. | % | No. | % | No. | % |
| 2024 | 5,998 | 79.71% | 1,428 | 18.98% | 99 | 1.32% |
| 2020 | 5,861 | 77.62% | 1,569 | 20.78% | 121 | 1.60% |
| 2016 | 5,752 | 77.67% | 1,315 | 17.76% | 339 | 4.58% |
| 2012 | 5,266 | 71.73% | 1,969 | 26.82% | 106 | 1.44% |
| 2008 | 4,894 | 66.74% | 2,338 | 31.88% | 101 | 1.38% |
| 2004 | 5,328 | 68.92% | 2,330 | 30.14% | 73 | 0.94% |
| 2000 | 4,674 | 66.35% | 2,170 | 30.81% | 200 | 2.84% |
| 1996 | 3,877 | 57.56% | 2,236 | 33.20% | 622 | 9.24% |
| 1992 | 3,869 | 51.06% | 2,122 | 28.00% | 1,587 | 20.94% |
| 1988 | 4,241 | 59.97% | 2,768 | 39.14% | 63 | 0.89% |
| 1984 | 5,008 | 66.16% | 2,479 | 32.75% | 82 | 1.08% |
| 1980 | 4,937 | 63.61% | 2,210 | 28.48% | 614 | 7.91% |
| 1976 | 4,643 | 61.86% | 2,732 | 36.40% | 131 | 1.75% |
| 1972 | 5,159 | 68.87% | 2,224 | 29.69% | 108 | 1.44% |
| 1968 | 5,594 | 69.34% | 2,146 | 26.60% | 328 | 4.07% |
| 1964 | 4,336 | 50.20% | 4,295 | 49.73% | 6 | 0.07% |
| 1960 | 6,509 | 68.66% | 2,967 | 31.30% | 4 | 0.04% |
| 1956 | 6,138 | 67.32% | 2,970 | 32.57% | 10 | 0.11% |
| 1952 | 7,130 | 76.18% | 2,192 | 23.42% | 38 | 0.41% |
| 1948 | 3,697 | 50.46% | 3,421 | 46.70% | 208 | 2.84% |
| 1944 | 4,033 | 56.01% | 3,138 | 43.58% | 30 | 0.42% |
| 1940 | 4,760 | 53.30% | 4,133 | 46.28% | 38 | 0.43% |
| 1936 | 3,350 | 38.90% | 5,139 | 59.67% | 123 | 1.43% |
| 1932 | 3,213 | 40.94% | 4,503 | 57.38% | 132 | 1.68% |
| 1928 | 4,845 | 66.39% | 2,397 | 32.84% | 56 | 0.77% |
| 1924 | 4,172 | 58.47% | 756 | 10.60% | 2,207 | 30.93% |
| 1920 | 5,137 | 76.51% | 1,468 | 21.86% | 109 | 1.62% |
| 1916 | 2,021 | 52.53% | 1,787 | 46.45% | 39 | 1.01% |
| 1912 | 620 | 16.02% | 1,506 | 38.91% | 1,744 | 45.06% |
| 1908 | 1,912 | 57.69% | 1,326 | 40.01% | 76 | 2.29% |
| 1904 | 2,279 | 68.94% | 885 | 26.77% | 142 | 4.30% |
| 1900 | 2,386 | 61.16% | 1,461 | 37.45% | 54 | 1.38% |
| 1896 | 2,421 | 60.10% | 1,562 | 38.78% | 45 | 1.12% |