Data / Rankings / Population under 18 / Counties in Montana

Counties in Montana by population under 18

Big Horn County had the highest population under 18 of 56 counties in 2014, at 33.4%. Powell County had the lowest, at 15.8%. The median was 21.4% and the figure for Montana was 22.2%. Source: the U.S. Census Bureau.

Highest33.4Big Horn County
Lowest15.8Powell County
Median21.456 counties
Montana22.2History

All counties, 2014

Big Horn County: 33.4 %Big Horn County33.4Glacier County: 31.2 %Glacier County31.2Roosevelt County: 31.1 %Roosevelt County31.1Blaine County: 29.6 %Blaine County29.6Rosebud County: 28.5 %Rosebud County28.5Hill County: 26.5 %Hill County26.5Chouteau County: 26.2 %Chouteau County26.2Fallon County: 25.8 %Fallon County25.8Pondera County: 25 %Pondera County25Lake County: 24.7 %Lake County24.7Richland County: 24.6 %Richland County24.6Garfield County: 23.9 %Garfield County23.9Yellowstone County: 23.7 %Yellowstone County23.7Valley County: 23 %Valley County23Sweet Grass County: 22.9 %Sweet Grass County22.9Liberty County: 22.8 %Liberty County22.8Custer County: 22.8 %Custer County22.8Flathead County: 22.7 %Flathead County22.7Teton County: 22.7 %Teton County22.7Wibaux County: 22.7 %Wibaux County22.7Phillips County: 22.6 %Phillips County22.6Dawson County: 22.5 %Dawson County22.5Cascade County: 22.5 %Cascade County22.5Wheatland County: 22.1 %Wheatland County22.1Lewis and Clark County: 22 %Lewis and Clark County22Daniels County: 21.7 %Daniels County21.7Stillwater County: 21.6 %Stillwater County21.6Petroleum County: 21.5 %Petroleum County21.5Jefferson County: 21.4 %Jefferson County21.4Broadwater County: 21.3 %Broadwater County21.3Gallatin County: 20.8 %Gallatin County20.8Sheridan County: 20.6 %Sheridan County20.6Ravalli County: 20.6 %Ravalli County20.6McCone County: 20.6 %McCone County20.6Fergus County: 20.4 %Fergus County20.4Silver Bow County: 20.4 %Silver Bow County20.4Missoula County: 19.8 %Missoula County19.8Musselshell County: 19.8 %Musselshell County19.8Golden Valley County: 19.8 %Golden Valley County19.8Toole County: 19.2 %Toole County19.2Park County: 19.1 %Park County19.1Beaverhead County: 19 %Beaverhead County19Carbon County: 18.9 %Carbon County18.9Lincoln County: 18.6 %Lincoln County18.6Sanders County: 18.6 %Sanders County18.6Mineral County: 18.5 %Mineral County18.5Treasure County: 18.5 %Treasure County18.5Carter County: 18.4 %Carter County18.4Powder River County: 18.4 %Powder River County18.4Granite County: 18.3 %Granite County18.3Judith Basin County: 18.3 %Judith Basin County18.3Meagher County: 18 %Meagher County18Deer Lodge County: 17.5 %Deer Lodge County17.5Prairie County: 17.5 %Prairie County17.5Madison County: 16.3 %Madison County16.3Powell County: 15.8 %Powell County15.8
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2014 (%)Change on 2013
1Big Horn County33.4+0.3 pts
2Glacier County31.2-0 pts
3Roosevelt County31.1+0.8 pts
4Blaine County29.6+0.2 pts
5Rosebud County28.5-0.1 pts
6Hill County26.5-0.3 pts
7Chouteau County26.2+0.4 pts
8Fallon County25.8+1.3 pts
9Pondera County25-0.2 pts
10Lake County24.7-0.2 pts
11Richland County24.6+0.8 pts
12Garfield County23.9-0.1 pts
13Yellowstone County23.70 pts
14Valley County23-0.2 pts
15Sweet Grass County22.9-0.2 pts
16Liberty County22.8+0.3 pts
17Custer County22.8+0.1 pts
18Flathead County22.7-0 pts
19Teton County22.7-0.3 pts
20Wibaux County22.7+0.8 pts
21Phillips County22.6+0.3 pts
22Dawson County22.5+0.7 pts
23Cascade County22.5-0.1 pts
24Wheatland County22.1-0.4 pts
25Lewis and Clark County22-0.1 pts
26Daniels County21.7+1.3 pts
27Stillwater County21.6-0.5 pts
28Petroleum County21.5-0.3 pts
29Jefferson County21.4-0.2 pts
30Broadwater County21.3-0.3 pts
31Gallatin County20.8-0.1 pts
32Sheridan County20.6+0.4 pts
33Ravalli County20.6-0.4 pts
34McCone County20.6+0.7 pts
35Fergus County20.4-0.1 pts
35Silver Bow County20.4-0.1 pts
37Missoula County19.80 pts
38Musselshell County19.8-0.9 pts
39Golden Valley County19.8-0.9 pts
40Toole County19.2-0.3 pts
41Park County19.1+0.2 pts
42Beaverhead County19+0.3 pts
43Carbon County18.9-0.4 pts
44Lincoln County18.6-0.3 pts
45Sanders County18.60 pts
46Mineral County18.5+0.2 pts
47Treasure County18.5+1.5 pts
48Carter County18.4+0.6 pts
49Powder River County18.40 pts
50Granite County18.3+0.5 pts
51Judith Basin County18.3+0.2 pts
52Meagher County18-0.3 pts
53Deer Lodge County17.5-0.5 pts
54Prairie County17.5+0.6 pts
55Madison County16.3-0.4 pts
56Powell County15.8-0.4 pts

Other periods

About this ranking

Residents aged 0 to 17 as a percentage of total population on 1 July. United States: Census Bureau county population estimates by age; states and the nation are sums of their counties.

Uses the US age of majority. Not comparable with population_0_14_share, which stops at 14.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties (Counties in Montana by population under 18, 2014) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html

MLA 9

Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Montana by population under 18, 2014. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-under-18/montana-counties?period=2014. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Counties in Montana by population under 18, 2014. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/population-under-18/montana-counties?period=2014.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Montana by population under 18, 2014 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-under-18/montana-counties?period=2014 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_montana_by_2014,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Montana by population under 18, 2014}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/population-under-18/montana-counties?period=2014. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Montana by population under 18, 2014
PY  - 2026
DA  - 2026/06/25
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2  - https://invokely.ai/rankings/population-under-18/montana-counties?period=2014
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/montana-counties?period=2014.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER  -
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Questions

Which county has the highest population under 18?

Big Horn County, with 33.4% in 2014, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Powell County, with 15.8% in 2014.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Retrieved 2026-10-12.

Population under 18: other rankings

Counties in Montana: more rankings