RANKING · 2020 CENSUS · 67 SHOWN OF 67

Most population gained, Pennsylvania counties · 2020

Pennsylvania counties that added the most residents from the 2010 census to 2020, by raw count of people rather than percentage. This list covers the 67 counties in Pennsylvania that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS 2000

01Philadelphia County, PAPA1,574,281+77,791−214%

02Montgomery County, PAPA877,643+56,679−21%

03Chester County, PAPA557,116+35,527−38%

04Lancaster County, PAPA563,159+33,539−30%

05Allegheny County, PAPA1,225,035+27,230−150%

06Lehigh County, PAPA384,383+25,060+20%

07Cumberland County, PAPA277,270+24,063+31%

08York County, PAPA473,197+21,466−49%

09Bucks County, PAPA647,828+21,289−62%

10Dauphin County, PAPA293,351+18,301+31%

11Delaware County, PAPA580,937+17,851+456%

12Berks County, PAPA440,072+17,407−53%

13Northampton County, PAPA324,411+15,216−24%

14Butler County, PAPA200,169+9,901−55%

15Lebanon County, PAPA146,380+9,689+47%

16Franklin County, PAPA160,652+6,314−23%

17Luzerne County, PAPA332,126+4,676−153%

18Centre County, PAPA157,393+4,182−65%

19Adams County, PAPA107,594+2,445−81%

20Washington County, PAPA210,802+1,529−191%

21Lackawanna County, PAPA216,502+1,459−125%

22Pike County, PAPA62,808+1,166−94%

23Snyder County, PAPA39,655+34−96%

24Perry County, PAPA46,806-127−105%

25Montour County, PAPA17,868-131−126%

26Fulton County, PAPA14,483-289−168%

27Carbon County, PAPA65,868-500−126%

28Cameron County, PAPA4,211-538−982%

29Mifflin County, PAPA46,127-539−287%

30Sullivan County, PAPA5,856-588−230%

31Jefferson County, PAPA43,255-708+369%

32Forest County, PAPA6,614-743−616%

33Tioga County, PAPA40,502-936−479%

34Elk County, PAPA29,926-956−509%

35Potter County, PAPA15,897-1,061−178%

36Clearfield County, PAPA78,100-1,080−120%

37Juniata County, PAPA23,403-1,127−151%

38Monroe County, PAPA167,179-1,515−104%

39Wayne County, PAPA51,703-1,667−121%

40Clinton County, PAPA37,870-1,788−344%

41Huntingdon County, PAPA43,001-1,821−228%

42Lycoming County, PAPA112,587-1,923−244%

43Bedford County, PAPA47,480-2,185−206%

44Wyoming County, PAPA25,790-2,207−55275%

45Union County, PAPA42,313-2,266−142%

46Beaver County, PAPA166,032-2,324−50%

47Columbia County, PAPA66,193-2,568−371%

48Bradford County, PAPA59,600-2,655−248%

49Greene County, PAPA33,885-2,732−343%

50Clarion County, PAPA36,680-2,747−4262%

51Northumberland County, PAPA89,920-2,881+30%

52McKean County, PAPA38,984-3,018+153%

53Warren County, PAPA37,038-3,228+172%

54Armstrong County, PAPA63,698-3,383+212%

55Somerset County, PAPA72,004-3,613−300%

56Blair County, PAPA119,541-4,267+205%

57Venango County, PAPA49,346-4,530+149%

58Crawford County, PAPA81,792-4,827−215%

59Susquehanna County, PAPA38,237-4,922−365%

60Lawrence County, PAPA83,911-5,038+214%

61Schuylkill County, PAPA145,085-5,240+133%

62Indiana County, PAPA82,878-5,634+1348%

63Mercer County, PAPA107,860-5,986+743%

64Fayette County, PAPA123,021-7,802−337%

65Erie County, PAPA265,832-9,690−284%

66Cambria County, PAPA128,968-10,207−2%

67Westmoreland County, PAPA349,324-10,506+3103%

SHOWING 1–67 OF 67

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS