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Most densely populated counties

Population per square mile of land, using the latest Census Bureau estimate and Gazetteer land area. Small urban counties and independent cities lead because a large population shares little land.

Ranks 301–400

Vintage 2025 population estimates · 2026 Gazetteer land area · 3,222 county equivalents · page 4 of 33

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What this part of the ranking shows

This page runs from James City County, Virginia at 586 people per mi² to Snohomish County, Washington at 417 people per mi². The 100 entries represent 34 state-level jurisdictions. Puerto Rico has the most entries on this page (11).

Rank numbers continue across pages and describe the full selected ranking. They are not state ranks. Start at rank 1 for the leading entries, or open a county profile for its state rank and median comparisons.

Most densely populated counties, ranks 301 through 400. Population is the July 1, 2025 estimate; density is per square mile of land.
RankCounty / equivalentStatePopulationPer mi²Land mi²
301James City CountyVirginia83,326586142.3
302Columbia CountyGeorgia169,189583290.2
303Santa Cruz CountyCalifornia258,852582445.1
304Hall CountyGeorgia226,568577392.5
305St. Johns CountyFlorida346,328577600.7
306Bernalillo CountyNew Mexico667,6015751,161.7
307Richland CountySouth Carolina434,956574757.3
308Santa Isabel MunicipioPuerto Rico19,54757334.1
309Pierce CountyWashington946,2885671,668
310San Germán MunicipioPuerto Rico30,80956654.4
311Cleveland CountyOklahoma303,973564538.9
312Dauphin CountyPennsylvania293,351559524.9
313Solano CountyCalifornia455,376554821.7
314San Sebastián MunicipioPuerto Rico39,01955470.5
315Floyd CountyIndiana82,153553148.5
316Winnebago CountyIllinois283,674553513
317Volusia CountyFlorida606,5735511,101.3
318Ottawa CountyMichigan308,459547563.5
319Delaware CountyOhio242,032546443.1
320Mahoning CountyOhio224,706546411.5
321Johnson CountyIndiana174,262544320.4
322Madison CountyAlabama433,516541801.7
323Sedgwick CountyKansas538,433540997
324Pulaski CountyArkansas404,611534758.4
325McHenry CountyIllinois317,751527603.4
326Washtenaw CountyMichigan370,214524706
327Guayama MunicipioPuerto Rico34,04352365
328York CountyPennsylvania473,197523904.4
329Ingham CountyMichigan289,709521556.1
330Brown CountyWisconsin275,803520530.1
331Ada CountyIdaho546,1415191,052.3
332Cumberland CountyNorth Carolina338,473519652.6
333Orange CountyNew York417,669514812.1
334Berks CountyPennsylvania440,072514856.4
335Maricopa CountyArizona4,689,5585109,202
336Cumberland CountyPennsylvania277,270508545.5
337Yabucoa MunicipioPuerto Rico28,05850855.2
338Escambia CountyFlorida333,834508657
339Atlantic CountyNew Jersey278,657502555.6
340Hillsborough CountyNew Hampshire433,415494876.5
341Dane CountyWisconsin590,3754931,196.5
342Marin CountyCalifornia253,694488520.1
343Cameron CountyTexas433,946487891.7
344Polk CountyFlorida874,7904861,798.8
345Clermont CountyOhio216,977479452.6
346Lake CountyFlorida456,068478954
347Maunabo MunicipioPuerto Rico10,12047821.2
348Hendricks CountyIndiana193,510476406.9
349Douglas CountyColorado399,396475840.1
350Adams CountyColorado554,6684751,166.8
351Charleston CountySouth Carolina436,200475918.3
352Southeastern Connecticut Planning RegionConnecticut284,015475598.1
353Houston CountyGeorgia178,214474376.2
354Lackawanna CountyPennsylvania216,502472458.8
355Spartanburg CountySouth Carolina380,857471808.4
356Kalamazoo CountyMichigan263,795469562
357Hernando CountyFlorida221,701469473
358Canyon CountyIdaho275,123469587
359Williamson CountyTennessee272,061467582.9
360Yauco MunicipioPuerto Rico31,60846767.8
361Rockingham CountyNew Hampshire324,077466695.6
362Ascension ParishLouisiana135,105466290
363Norton cityVirginia3,4774657.5
364Montgomery CountyTennessee249,935464539.2
365Gregg CountyTexas126,095461273.4
366Newton CountyGeorgia125,583459273.8
367Frederick CountyMaryland302,883458660.7
368Greene CountyMissouri309,286458675.3
369Weber CountyUtah278,174455611
370Lexington CountySouth Carolina317,588455698.5
371Kendall CountyIllinois145,470454320.2
372Boulder CountyColorado328,560452726.4
373Lares MunicipioPuerto Rico27,74445261.4
374Ventura CountyCalifornia830,8514511,840.8
375York CountySouth Carolina306,887451680.6
376Elkhart CountyIndiana208,774451463.2
377Hays CountyTexas304,390450676.9
378Leon CountyFlorida299,048447668.4
379Scott CountyMinnesota159,017447356.1
380Calvert CountyMaryland94,484443213.2
381Alamance CountyNorth Carolina186,177440423.5
382Medina CountyOhio185,025439421.5
383Naguabo MunicipioPuerto Rico22,66643951.7
384Berkeley CountyWest Virginia139,522434321.1
385Peñuelas MunicipioPuerto Rico19,32543344.7
386Washington CountyTennessee141,199432326.5
387Putnam CountyNew York99,028430230.3
388Catoosa CountyGeorgia69,628429162.2
389Hamblen CountyTennessee68,843427161.2
390Brazos CountyTexas249,088425586.2
391Coamo MunicipioPuerto Rico33,07642478
392Catawba CountyNorth Carolina170,172424401.4
393Union CountyNorth Carolina267,674423632.7
394Buncombe CountyNorth Carolina277,417423656.5
395Greene CountyOhio174,322421413.6
396Thurston CountyWashington304,261421722.5
397Porter CountyIndiana176,049421418.1
398Nueces CountyTexas352,992421839.4
399Lower Connecticut River Valley Planning RegionConnecticut177,311418424.1
400Snohomish CountyWashington870,6564172,086.5

Read the differences behind ranks 301–400

The median density among these 100 entries is 475 people per mi². The first and last entries span 168 people per square mile. This median describes the entries on this page, not the full national dataset. Pagination is a browsing boundary, not a distinct geographic region.

Adjacent ranks can differ by a handful of residents or by many thousands. Open a county profile for its population trend since 2020, land area, and state comparisons.

Where the entries on this page are located

  • Puerto Rico11 entries · 11% of this page
  • Florida7 entries · 7% of this page
  • Georgia5 entries · 5% of this page
  • Indiana5 entries · 5% of this page
  • North Carolina5 entries · 5% of this page
  • Ohio5 entries · 5% of this page

The remaining 28 jurisdictions contribute 62 entries. The list above shows the six most represented, with alphabetical ordering when counts tie.

These counts describe representation in this slice of the ranking. They do not measure a state’s share of national land or population. Compare the first and last county equivalents on this page to inspect land, water, and total area separately.

Read the geographic explanation behind this ranking, or return to the ranking overview for the national distribution and guidance on selecting a measurement.

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Population rankings use Census Bureau Vintage 2025 estimates; density rankings divide them by original ALAND square meters. Land rankings use original ALAND square meters; total-area rankings use ALAND + AWATER. Exact ties use ascending GEOID. Displayed square-mile values are rounded. Read the methodology.