State ranking

How much of each state lives in one county

The share of each state's residents who live in its most populous county-equivalent.

Short answer

In Nevada, 73.4% of residents live in Clark County, the highest share of any state. In Mississippi the largest county, Harrison County, holds only 7.3%.
#1 Nevada
73.4%
  1. 01Nevada73.4%
  2. 02Hawaii69.1%
  3. 03Arizona61.6%
  4. 04Rhode Island60.8%
  5. 05Delaware55.9%
  6. 06Illinois40.8%
  7. 07Alaska39.1%
  8. 08Utah34.7%
  9. 09New Mexico31.5%
  10. 10New Hampshire30.6%
  11. 11Nebraska30.0%
  12. 12Washington29.4%
  13. 13Connecticut27.0%
  14. 14Idaho26.8%
  15. 15Vermont26.3%
  16. 16North Dakota25.2%
  17. 17California24.7%
  18. 18Massachusetts23.4%
  19. 19South Dakota22.6%
  20. 20Maine22.3%
  21. 21Minnesota22.0%
  22. 22Kansas21.3%
  23. 23Oklahoma19.9%
  24. 24Oregon18.6%
  25. 25Michigan17.5%
  26. 26Wyoming17.3%
  27. 27Kentucky17.3%
  28. 28Maryland17.3%
  29. 29Texas16.0%
  30. 30Iowa15.9%
  31. 31Missouri15.9%
  32. 32Wisconsin15.5%
  33. 33Montana15.1%
  34. 34Indiana14.2%
  35. 35New York13.2%
  36. 36Virginia13.2%
  37. 37Arkansas13.0%
  38. 38Alabama12.9%
  39. 39Colorado12.6%
  40. 40Tennessee12.6%
  41. 41Florida12.1%
  42. 42Pennsylvania12.0%
  43. 43Ohio11.4%
  44. 44North Carolina11.2%
  45. 45South Carolina10.4%
  46. 46New Jersey10.3%
  47. 47Louisiana9.9%
  48. 48West Virginia9.8%
  49. 49Georgia9.8%
  50. 50Mississippi7.3%
Share in top county. Rank 1 at the top.
GeorgiaIndianaMaineMinnesotaNorth DakotaColoradoAlaskaArkansasIllinoisIowaMississippiNew YorkTennesseeTexasVirginiaKansasAlabamaNorth CarolinaMichiganMissouriNebraskaOhioSouth CarolinaVermontWisconsinCaliforniaKentuckySouth DakotaNevadaFloridaMarylandPennsylvaniaArizonaRhode IslandIdahoOregonMontanaWashingtonWest VirginiaNew MexicoNew HampshireOklahomaUtahWyomingHawaiiLouisianaMassachusettsConnecticutNew JerseyDelawareDistrict of Columbia

Darker states rank higher. Alaska and Hawaii are insets.

Each state's largest county

5 states have more than half of their residents in a single county, and 17 have less than 15%. The median state has 17.4% in its top county.

StateLargest countyResidentsShare
NevadaClark County2,398,87173.4%
HawaiiHonolulu County998,74769.1%
ArizonaMaricopa County4,673,09661.6%
Rhode IslandProvidence County675,91260.8%
DelawareNew Castle County588,09355.9%
IllinoisCook County5,182,61740.8%
AlaskaAnchorage289,60039.1%
UtahSalt Lake County1,216,27434.7%
New MexicoBernalillo County671,74731.5%
New HampshireHillsborough County430,46230.6%
NebraskaDouglas County601,15830.0%
WashingtonKing County2,340,21129.4%
ConnecticutCapitol Planning Region991,50827.0%
IdahoAda County535,79926.8%
VermontChittenden County170,85126.3%
North DakotaCass County200,94525.2%
CaliforniaLos Angeles County9,757,17924.7%
MassachusettsMiddlesex County1,668,95623.4%
South DakotaMinnehaha County208,63922.6%
MaineCumberland County313,80922.3%
MinnesotaHennepin County1,273,33422.0%
KansasJohnson County632,27621.3%
OklahomaOklahoma County816,49019.9%
OregonMultnomah County795,89718.6%
MichiganWayne County1,771,06317.5%
WyomingLaramie County101,78317.3%
KentuckyJefferson County793,88117.3%
MarylandMontgomery County1,082,27317.3%
TexasHarris County5,009,30216.0%
IowaPolk County516,18515.9%
MissouriSt. Louis County992,92915.9%
WisconsinMilwaukee County924,74015.5%
MontanaYellowstone County171,58315.1%
IndianaMarion County981,62814.2%
New YorkKings County2,617,63113.2%
VirginiaFairfax County1,160,92513.2%
ArkansasPulaski County401,20913.0%
AlabamaJefferson County664,74412.9%
ColoradoEl Paso County752,77212.6%
TennesseeShelby County910,53012.6%
FloridaMiami-Dade County2,838,46112.1%
PennsylvaniaPhiladelphia County1,573,91612.0%
OhioFranklin County1,356,30311.4%
North CarolinaWake County1,232,44411.2%
South CarolinaGreenville County570,74510.4%
New JerseyBergen County978,64110.3%
LouisianaEast Baton Rouge Parish453,0229.9%
West VirginiaKanawha County173,9069.8%
GeorgiaFulton County1,090,3549.8%
MississippiHarrison County213,7307.3%

How the share is computed

The largest county's Vintage 2024 population divided by the sum of all county estimates in the state. DC is left out because it is a single county-equivalent and would always score 100%. A high share says the state's people are concentrated around one metro; it says nothing about how large that county is in land.

Questions people ask

Which state has the most people in one county?

Nevada, where 73.4% of residents live in Clark County.

Which state is least concentrated?

Mississippi, where the largest county holds 7.3%.

Why is DC not ranked?

DC is one county-equivalent, so its share is always 100%.

Suggested citation

Online Map Tools. "How much of each state lives in one county." Published 2026-09-30. https://onlinemaptools.com/rankings/states-by-population-in-largest-county. Data: Census Vintage 2024 county population estimates.

Journalists, students and researchers may quote these figures and reuse the table. Please credit Online Map Tools and link to this page. The underlying government data is in the public domain.

Download the data (CSV)

Sources and data as of

Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.

  1. 01Census Vintage 2024 county population estimates

How every number is computed: methodology. Spotted a wrong figure? Report an error.

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