Demographics of O'Brien County, Iowa

O'Brien County, Iowa had 14,220 people on July 1, 2025, by the Census Bureau’s estimate: +64 since July 2020. Age, income, poverty, housing and origin below come from the American Community Survey, averaged over 2020–2024, each with its margin of error.

O'Brien County, in four figures

14,220
Population: July 1, 2025, Vintage 2025 estimate.; +0.5%
Change since July 2020: +64 people.; 39.5 ±0.8
Median age: ACS 2020–⁠2024.; $68,356 ±$4,388
Median household income: ACS 2020–⁠2024, in 2024 dollars.

Population, year by year

July 1 estimates from the Census Bureau’s Vintage 2025. Each year's change is births less deaths, net moves from abroad and net moves from elsewhere in the country, with the Bureau's small residual. The 2020 row's components run 3 months, from the April census to July 1.

O'Brien County, Iowa's population grew 0.5% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of O'Brien County, Iowa's resident population and the nation's, each year of the Census Bureau's Vintage 2025, as a share of its July 2020 level (= 100).

U.S. Census Bureau — Census Bureau population estimates — counties and Puerto Rico municipios, with components of change

About this chart

The figures

O'Brien County, Iowa's population grew 0.5% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of O'Brien County, Iowa's resident population and the nation's, each year of the Census Bureau's Vintage 2025, as a share of its July 2020 level (= 100).
July 1	Population	Index	United States
2020	14,156	100.0	100.0
2021	14,052	99.3	100.2
2022	14,095	99.6	100.7
2023	14,052	99.3	101.6
2024	14,188	100.2	102.5
2025	14,220	100.5	103.1

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Population of O'Brien County, Iowa on July 1 of each year, Vintage 2025
July 1	Population	Change	Births less deaths	From abroad	From elsewhere in the country
2020	14,156	−31	−11	0	−20
2021	14,052	−104	−60	+9	−58
2022	14,095	+43	+13	+46	−10
2023	14,052	−43	−5	+76	−117
2024	14,188	+136	−14	+58	+96
2025	14,220	+32	−21	+44	+9

Age, 2020–2024

The median age is 39.5 ±0.8: for men 38.4 ±0.9 and for women 40.6 ±1.3. Shares are of everyone the survey counts, in the Bureau’s sex-by-age table (B01001).

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People in O'Brien County by age, ACS 2020–2024
Age	People	Share	Iowa	United States
Under 5	965 ±73	6.8% ±0.5	5.9% ±<0.1	5.6% ±<0.1
5 to 17	2,481 ±221	17.6% ±1.6	17.0% ±0.1	16.3% ±<0.1
18 to 24	1,037 ±132	7.3% ±0.9	10.0% ±0.1	9.1% ±<0.1
25 to 44	3,485 ±254	24.7% ±1.8	25.1% ±0.1	26.9% ±<0.1
45 to 64	3,169 ±226	22.4% ±1.6	23.9% ±0.1	24.8% ±<0.1
65 and over	2,989 ±237	21.2% ±1.7	18.1% ±0.1	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $68,356 ±$4,388, and income per person $35,198 ±$1,453, in 2024 dollars. The median is $75,059 ±$418 in Iowa and $80,734 ±$166 in the United States.

Households by income

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Households in O'Brien County by income, ACS 2020–2024
Household income	Households	Share	Iowa	United States
Under $25,000	799 ±142	13.8% ±2.4	13.9% ±0.2	14.6% ±<0.1
$25,000 to $49,999	1,108 ±204	19.1% ±3.4	18.5% ±0.3	16.7% ±<0.1
$50,000 to $74,999	1,175 ±193	20.2% ±3.2	17.5% ±0.3	15.5% ±<0.1
$75,000 to $99,999	887 ±139	15.3% ±2.3	14.0% ±0.3	12.6% ±<0.1
$100,000 to $149,999	1,068 ±176	18.4% ±2.9	18.7% ±0.3	17.5% ±<0.1
$150,000 to $199,999	516 ±144	8.9% ±2.5	8.8% ±0.2	9.6% ±<0.1
$200,000 or more	256 ±89	4.4% ±1.5	8.6% ±0.2	13.4% ±0.1

Poverty by age

The poverty rate is the share of people whose family income is below the federal threshold for their family’s size, of everyone for whom the Bureau determines it (B17020).

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Poverty rate in O'Brien County by age, ACS 2020–2024
Age	Below poverty	Rate	Iowa	United States
All ages	1,841 ±370	13.3% ±2.7	11.1% ±0.2	12.5% ±0.1
Under 18	713 ±159	20.7% ±4.3	12.9% ±0.3	16.1% ±0.1
18 to 59	748 ±179	11.3% ±2.6	11.4% ±0.3	11.6% ±0.1
60 and over	380 ±146	10.2% ±3.8	8.8% ±0.2	11.0% ±<0.1

Housing, 2020–2024

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Housing in O'Brien County, ACS 2020–2024
Measure	O'Brien County	Iowa	United States
Housing units	6,564 ±32	1,437,699 ±523	143,775,355 ±10,234
Occupied	88.5% ±3.5	91.5% ±0.3	89.9% ±0.1
Vacant	11.5% ±3.5	8.5% ±0.3	10.1% ±0.1
Owner occupied	76.1% ±3.3	71.7% ±0.3	65.2% ±0.3
Renter occupied	23.9% ±3.9	28.3% ±0.3	34.8% ±0.1
Median home value	$173,100 ±$9,272	$208,000 ±$1,141	$332,700 ±$236
Median gross rent	$868 ±$94	$972 ±$6	$1,413 ±$2
Median year built	1959 ±3	1972 ±1	1980 ±1

Occupied and vacant are shares of all housing units; owner and renter occupied are shares of occupied units. Value and rent are medians in 2024 dollars.

Origin and place of birth, 2020–2024

Hispanic or Latino origin is not a race in the Census Bureau’s tables. Here the people of Hispanic origin, of any race, are one row, and everyone else is counted by race alone (B03002), so the rows add to the whole.

Hispanic origin and race

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People in O'Brien County by Hispanic origin and race, ACS 2020–2024
Origin	People	Share	Iowa	United States
Hispanic or Latino	1,074 ±0	7.6% ±<0.1	7.3% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	12,288 ±139	87.0% ±1.0	82.3% ±0.1	57.4% ±<0.1
Black alone, not Hispanic	240 ±48	1.7% ±0.3	3.8% ±0.1	11.9% ±<0.1
Asian alone, not Hispanic	92 ±32	0.7% ±0.2	2.5% ±<0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	1 to 47	< 0.1% to 0.3%	0.2% ±<0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	22 ±10	0.2% ±0.1	0.2% ±<0.1	0.2% ±<0.1
Some other race alone, not Hispanic	0 to 47	0% to 0.3%	0.3% ±<0.1	0.6% ±<0.1
Two or more races, not Hispanic	366 ±152	2.6% ±1.1	3.5% ±0.1	4.3% ±<0.1

A range (the estimate less and plus its margin) where the Bureau's estimate is too uncertain to state as one number: a coefficient of variation over 30%.

Place of birth and citizenship

“Born a citizen outside the states” counts people born in Puerto Rico, the island areas, or abroad to American parents. Naturalized citizens and those who are not citizens together make up the people born abroad (B05002).

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People in O'Brien County by place of birth and citizenship, ACS 2020–2024
Born	People	Share	Iowa	United States
Born in the state	10,828 ±254	76.7% ±1.8	69.6% ±0.2	57.3% ±<0.1
Born in another state	2,385 ±278	16.9% ±2.0	23.8% ±0.2	26.9% ±<0.1
Born a citizen outside the states	286 ±50	2.0% ±0.4	0.7% ±<0.1	1.7% ±<0.1
Born abroad	627 ±130	4.4% ±0.9	5.9% ±0.1	14.1% ±<0.1
Naturalized citizens	79 to 313	0.6% to 2.2%	2.6% ±0.1	7.4% ±<0.1
Not citizens	431 ±176	3.1% ±1.2	3.3% ±0.1	6.8% ±<0.1

A range (the estimate less and plus its margin) where the Bureau's estimate is too uncertain to state as one number: a coefficient of variation over 30%.

O'Brien County among the counties of Iowa

56th of 99 by population, July 2025. Every one is listed on the Iowa page.

Counties of Iowa near O'Brien County in population, July 2025
County	July 2025	Change since 2020
Page County	14,856	−2.3%
Mills County	14,793	+2.6%
Harrison County	14,623	+0.4%
Kossuth County	14,322	−3.2%
Allamakee County	14,238	+1.2%
O'Brien County	14,220	+0.5%
Butler County	14,049	−2.0%
Cass County	12,960	−1.2%
Wright County	12,801	−0.9%
Grundy County	12,361	+0.2%
Lyon County	12,354	+3.6%

Elsewhere on the site

Sources

Census Bureau population estimates — counties and Puerto Rico municipios, with components of change — U.S. Census Bureau · U.S. Government work · retrieved September 25, 2026
American Community Survey 5-year estimates — table-based Summary File · U.S. Government work

Data retrieved September 25, 2026