State ranking

The most populous county in every state

Each state's most populous county-equivalent, ranked by Vintage 2024 population.

Short answer

California: Los Angeles County is the most populous state-leading county with 9,757,179 residents. The smallest state-leading county is Wyoming: Laramie County, with 101,783.
#1 California: Los Angeles County
9,757,179
  1. 01California: Los Angeles County9,757,179
  2. 02Illinois: Cook County5,182,617
  3. 03Texas: Harris County5,009,302
  4. 04Arizona: Maricopa County4,673,096
  5. 05Florida: Miami-Dade County2,838,461
  6. 06New York: Kings County2,617,631
  7. 07Nevada: Clark County2,398,871
  8. 08Washington: King County2,340,211
  9. 09Michigan: Wayne County1,771,063
  10. 10Massachusetts: Middlesex County1,668,956
  11. 11Pennsylvania: Philadelphia County1,573,916
  12. 12Ohio: Franklin County1,356,303
  13. 13Minnesota: Hennepin County1,273,334
  14. 14North Carolina: Wake County1,232,444
  15. 15Utah: Salt Lake County1,216,274
  16. 16Virginia: Fairfax County1,160,925
  17. 17Georgia: Fulton County1,090,354
  18. 18Maryland: Montgomery County1,082,273
  19. 19Hawaii: Honolulu County998,747
  20. 20Missouri: St. Louis County992,929
  21. 21Connecticut: Capitol Planning Region991,508
  22. 22Indiana: Marion County981,628
  23. 23New Jersey: Bergen County978,641
  24. 24Wisconsin: Milwaukee County924,740
  25. 25Tennessee: Shelby County910,530
  26. 26Oklahoma: Oklahoma County816,490
  27. 27Oregon: Multnomah County795,897
  28. 28Kentucky: Jefferson County793,881
  29. 29Colorado: El Paso County752,772
  30. 30District of Columbia: District of Columbia702,250
  31. 31Rhode Island: Providence County675,912
  32. 32New Mexico: Bernalillo County671,747
  33. 33Alabama: Jefferson County664,744
  34. 34Kansas: Johnson County632,276
  35. 35Nebraska: Douglas County601,158
  36. 36Delaware: New Castle County588,093
  37. 37South Carolina: Greenville County570,745
  38. 38Idaho: Ada County535,799
  39. 39Iowa: Polk County516,185
  40. 40Louisiana: East Baton Rouge Parish453,022
  41. 41New Hampshire: Hillsborough County430,462
  42. 42Arkansas: Pulaski County401,209
  43. 43Maine: Cumberland County313,809
  44. 44Alaska: Anchorage289,600
  45. 45Mississippi: Harrison County213,730
  46. 46South Dakota: Minnehaha County208,639
  47. 47North Dakota: Cass County200,945
  48. 48West Virginia: Kanawha County173,906
  49. 49Montana: Yellowstone County171,583
  50. 50Vermont: Chittenden County170,851
  51. 51Wyoming: Laramie County101,783
Most populous county, residents. Log scale. 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.

The 51 leaders together

Together the 51 state-leading counties hold 67,469,421 residents, 19.8% of the US total. 18 of them have a million or more residents, and 7 have fewer than 250,000. The share of each state in its largest county shows how dominant each one is.

How this list is built

For each state, county-equivalents are sorted by their Census Vintage 2024 population estimate for July 1, 2024 and the first is kept. Independent cities count as their own units, so in Virginia and Maryland a city can lead if it is larger than every county.

Questions people ask

What is the most populous county in the US?

Los Angeles County, California, with 9,757,179 residents.

How many states have a county of a million people?

18 states have at least one county-equivalent of 1,000,000 or more residents.

Which data does this use?

Census Vintage 2024 county population estimates.

Suggested citation

Online Map Tools. "The most populous county in every state." Published 2026-09-30. https://onlinemaptools.com/rankings/most-populous-county-in-each-state. 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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