Data / Rankings / Median age / Counties in Montana

Counties in Montana by median age

Meagher County had the highest median age of 56 counties in 2021, at 56.3 years. Roosevelt County had the lowest, at 30.3 years. The median was 45.5 years and the figure for Montana was 40 years. Source: the U.S. Census Bureau.

Highest56.3Meagher County
Lowest30.3Roosevelt County
Median45.556 counties
Montana40History

All counties, 2021

CSVChart (SVG)

Meagher CountyMeagher County: 56.3 years56.3Carter CountyCarter County: 56.2 years56.2Treasure CountyTreasure County: 55.5 years55.5Granite CountyGranite County: 54.6 years54.6Golden Valley CountyGolden Valley County: 54.5 years54.5Sanders CountySanders County: 54.4 years54.4Madison CountyMadison County: 54 years54Lincoln CountyLincoln County: 52.9 years52.9McCone CountyMcCone County: 52.5 years52.5Judith Basin CountyJudith Basin County: 52.3 years52.3Musselshell CountyMusselshell County: 52.1 years52.1Mineral CountyMineral County: 51 years51Carbon CountyCarbon County: 50.7 years50.7Petroleum CountyPetroleum County: 50 years50Ravalli CountyRavalli County: 49.1 years49.1Daniels CountyDaniels County: 48.6 years48.6Wheatland CountyWheatland County: 48.6 years48.6Powder River CountyPowder River County: 48.5 years48.5Deer Lodge CountyDeer Lodge County: 48.4 years48.4Stillwater CountyStillwater County: 48.3 years48.3Prairie CountyPrairie County: 48.1 years48.1Wibaux CountyWibaux County: 47.7 years47.7Jefferson CountyJefferson County: 47.5 years47.5Broadwater CountyBroadwater County: 46.9 years46.9Phillips CountyPhillips County: 46.7 years46.7Park CountyPark County: 46.3 years46.3Powell CountyPowell County: 45.7 years45.7Fergus CountyFergus County: 45.5 years45.5Sweet Grass CountySweet Grass County: 45.4 years45.4Sheridan CountySheridan County: 45.1 years45.1Valley CountyValley County: 43.6 years43.6Garfield CountyGarfield County: 43.1 years43.1Custer CountyCuster County: 43 years43Lake CountyLake County: 42.7 years42.7Teton CountyTeton County: 42.5 years42.5Beaverhead CountyBeaverhead County: 42.4 years42.4Flathead CountyFlathead County: 42.3 years42.3Chouteau CountyChouteau County: 42.1 years42.1Toole CountyToole County: 41.8 years41.8Pondera CountyPondera County: 41.3 years41.3Dawson CountyDawson County: 41.1 years41.1Lewis and Clark CountyLewis and Clark County: 40.9 years40.9Silver Bow CountySilver Bow County: 40.5 years40.5Liberty CountyLiberty County: 39.3 years39.3Yellowstone CountyYellowstone County: 38.5 years38.5Richland CountyRichland County: 38.3 years38.3Cascade CountyCascade County: 38 years38Rosebud CountyRosebud County: 36.7 years36.7Missoula CountyMissoula County: 36.3 years36.3Fallon CountyFallon County: 35.1 years35.1Hill CountyHill County: 34.1 years34.1Gallatin CountyGallatin County: 33.7 years33.7Glacier CountyGlacier County: 33.7 years33.7Blaine CountyBlaine County: 33.5 years33.5Big Horn CountyBig Horn County: 31.3 years31.3Roosevelt CountyRoosevelt County: 30.3 years30.3
years. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2021
years
1Meagher County56.3
2Carter County56.2
3Treasure County55.5
4Granite County54.6
5Golden Valley County54.5
6Sanders County54.4
7Madison County54
8Lincoln County52.9
9McCone County52.5
10Judith Basin County52.3
11Musselshell County52.1
12Mineral County51
13Carbon County50.7
14Petroleum County50
15Ravalli County49.1
16Daniels County48.6
16Wheatland County48.6
18Powder River County48.5
19Deer Lodge County48.4
20Stillwater County48.3
21Prairie County48.1
22Wibaux County47.7
23Jefferson County47.5
24Broadwater County46.9
25Phillips County46.7
26Park County46.3
27Powell County45.7
28Fergus County45.5
29Sweet Grass County45.4
30Sheridan County45.1
31Valley County43.6
32Garfield County43.1
33Custer County43
34Lake County42.7
35Teton County42.5
36Beaverhead County42.4
37Flathead County42.3
38Chouteau County42.1
39Toole County41.8
40Pondera County41.3
41Dawson County41.1
42Lewis and Clark County40.9
43Silver Bow County40.5
44Liberty County39.3
45Yellowstone County38.5
46Richland County38.3
47Cascade County38
48Rosebud County36.7
49Missoula County36.3
50Fallon County35.1
51Hill County34.1
52Gallatin County33.7
52Glacier County33.7
54Blaine County33.5
55Big Horn County31.3
56Roosevelt County30.3

Other periods

About this ranking

Age that divides the resident population into two halves of equal size. Spain and the EU: on 1 January. United States: American Community Survey five-year estimate, where the period shown is the last year of the five-year span.

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. American Community Survey 5-year estimates, table B01002: median age, total population. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b01002.dat. Retrieved 2026-10-08.

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Questions

Which county has the highest median age?

Meagher County, with 56.3 years in 2021, according to the U.S. Census Bureau.

Which county has the lowest median age?

Roosevelt County, with 30.3 years in 2021.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, American Community Survey 5-year estimates, table B01002: median age, total population. Retrieved 2026-10-08.

Median age: other rankings

Counties in Montana: more rankings