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Idaho population history

1,839,106

Idaho population at the decennial census, 2020

+17.3% since 2010 (1,567,582); +157.9% since 1970 (713,015); +325.9% since 1920 (431,866)

Source: U.S. Census Bureau, Decennial Census population counts. Data period 2020. Published . Newest release as of ; next edition expected in 2031.

Resident population as counted at the decennial census.

Comparison

Among 44 Idaho counties in 2020, Ada County was highest at 494,966 and Clark County lowest at 788.

Historical data

Idaho population history, 1870 to 2020Idaho population history, 1870 to 2020. Idaho: 14,999 in 1870, 1,839,106 in 2020.0500k1M1.5M2M19002000PeopleIdaho population history, 1870 to 2020Idaho population history, 1870 to 2020. Idaho: 14,999 in 1870, 1,839,106 in 2020.0500k1M1.5M2M190019502000PeopleIdaho population history, 1870 to 2020Idaho population history, 1870 to 2020. Idaho: 14,999 in 1870, 1,839,106 in 2020.0500k1M1.5M2M190019502000People

Source: Census Bureau, Decennial Census population counts.

Data table (16 rows)
PeriodIdaho (people)
187014,999
188032,610
189088,548
1900161,772
1910325,594
1920431,866
1930445,032
1940524,873
1950588,637
1960667,191
1970713,015
1980944,127
19901,006,734
20001,293,953
20101,567,582
20201,839,106

By county

Ada County: 494,966 People (2020)Adams County: 4,378 People (2020)Bannock County: 87,023 People (2020)Bear Lake County: 6,367 People (2020)Benewah County: 9,535 People (2020)Bingham County: 47,987 People (2020)Blaine County: 24,271 People (2020)Boise County: 7,612 People (2020)Bonner County: 47,114 People (2020)Bonneville County: 123,959 People (2020)Boundary County: 12,059 People (2020)Butte County: 2,573 People (2020)Camas County: 1,072 People (2020)Canyon County: 231,107 People (2020)Caribou County: 7,027 People (2020)Cassia County: 24,688 People (2020)Clark County: 788 People (2020)Clearwater County: 8,735 People (2020)Custer County: 4,277 People (2020)Elmore County: 28,665 People (2020)Franklin County: 14,196 People (2020)Fremont County: 13,387 People (2020)Gem County: 19,128 People (2020)Gooding County: 15,600 People (2020)Idaho County: 16,545 People (2020)Jefferson County: 30,891 People (2020)Jerome County: 24,241 People (2020)Kootenai County: 171,366 People (2020)Latah County: 39,521 People (2020)Lemhi County: 7,972 People (2020)Lewis County: 3,533 People (2020)Lincoln County: 5,129 People (2020)Madison County: 52,913 People (2020)Minidoka County: 21,584 People (2020)Nez Perce County: 42,089 People (2020)Oneida County: 4,565 People (2020)Owyhee County: 11,912 People (2020)Payette County: 25,378 People (2020)Power County: 7,877 People (2020)Shoshone County: 13,167 People (2020)Teton County: 11,637 People (2020)Twin Falls County: 90,050 People (2020)Valley County: 11,743 People (2020)Washington County: 10,496 People (2020)
  • 788 to 6,762
  • 6,763 to 11,776
  • 11,777 to 21,092
  • 21,093 to 44,098
  • 44,099 to 494,966

Source: Census Bureau, Decennial Census population counts.

Data table (44 rows)
County2020
Ada County494,966
Canyon County231,107
Kootenai County171,366
Bonneville County123,959
Twin Falls County90,050
Bannock County87,023
Madison County52,913
Bingham County47,987
Bonner County47,114
Nez Perce County42,089
Latah County39,521
Jefferson County30,891
Elmore County28,665
Payette County25,378
Cassia County24,688
Blaine County24,271
Jerome County24,241
Minidoka County21,584
Gem County19,128
Idaho County16,545
Gooding County15,600
Franklin County14,196
Fremont County13,387
Shoshone County13,167
Boundary County12,059
Owyhee County11,912
Valley County11,743
Teton County11,637
Washington County10,496
Benewah County9,535
Clearwater County8,735
Lemhi County7,972
Power County7,877
Boise County7,612
Caribou County7,027
Bear Lake County6,367
Lincoln County5,129
Oneida County4,565
Adams County4,378
Custer County4,277
Lewis County3,533
Butte County2,573
Camas County1,072
Clark County788
  • From the Population Estimates Program's Vintage 2025 April 1, 2020 base (ESTIMATESBASE2020), the Bureau's postcensal representation of the 2020 Census count; it can differ by a handful of people from the originally tabulated redistricting count.

Source

Organization
U.S. Census Bureau
Dataset
Decennial Census population counts
Geography
Idaho and its 44 counties
Time coverage
1870-2020
Update frequency
Decennial
Published
Newest release as of
; next edition expected in 2031
Original file
https://www2.census.gov/library/publications/2003/dec/phc-3-14.pdf
Methodology
https://www.census.gov/programs-surveys/decennial-census/about/history.html
License
Public domain. U.S. federal government work.
Our copy
Decennial Census population counts

Caveats

  • State totals for 1870-2000 are from the Census Bureau's 2003 report "Population and Housing Unit Counts, Idaho: 2000" (report PHC-3-14); totals for 2010 and 2020 are from the 2020 Census apportionment product (2026).
  • County totals cover 1960-2020 only; no source used here tabulates all 44 counties for an earlier census.
  • 2020 county values are the Population Estimates Program's postcensal estimates base, not the original 2020 Census redistricting tabulation.
  • Some county and state figures are the Census Bureau's later revision of the originally published census count, not the original figure.

Where sources disagree

  • Decennial census population, Idaho, 1970: U.S. Census Bureau, Population of States and Counties of the United States: 1790-1990 (March 1996) publishes 712,567. This dataset uses the 2003 report's 713,015. The 1996 compilation, and the 2020 Census apportionment product's historical table, both give 712,567 for the same census.
  • Decennial census population, Idaho, 1980: U.S. Census Bureau, Population of States and Counties of the United States: 1790-1990 (March 1996) publishes 943,935. This dataset uses the 2003 report's 944,127. The 1996 compilation, and the 2020 Census apportionment product's historical table, both give 943,935 for the same census.
  • Decennial census population, Idaho, 1990: U.S. Census Bureau, Population of States and Counties of the United States: 1790-1990 (March 1996) publishes 1,006,749. This dataset uses the 2003 report's 1,006,734, itself marked as a post-hoc revision in that table. The 1996 compilation, and the 2020 Census apportionment product's historical table, both give 1,006,749 for the same census.

Cite as Understand Idaho, “Idaho population history”, https://understandidaho.com/population/history/; cite the publisher above for the figures. See the data catalog.

This page was last updated .