Largest Cities in Sullivan County, PA by Population

Philadelphia County (1,578,487) Allegheny County (1,211,358) Montgomery County (833,869) Bucks County (627,987) Delaware County (566,753) Lancaster County (546,192) Chester County (526,759) York County (450,448) Berks County (421,017) Lehigh County (370,802) Westmoreland County (347,087) Luzerne County (316,982) Northampton County (305,892) Dauphin County (279,874) Erie County (268,426) Cumberland County (255,857) Lackawanna County (208,989) Washington County (206,803) Butler County (189,135) Monroe County (170,154) Beaver County (162,575) Centre County (161,496) Franklin County (155,637) Lebanon County (141,663) Schuylkill County (140,709) Cambria County (128,672) Fayette County (128,126) Blair County (121,007) Lycoming County (113,209) Mercer County (108,545) Adams County (102,742) Northumberland County (90,258) Lawrence County (85,083) Crawford County (83,697) Indiana County (83,664) Clearfield County (78,612) Somerset County (72,916) Columbia County (64,842) Armstrong County (64,162) Carbon County (64,081) Bradford County (60,221) Pike County (56,072) Wayne County (51,163) Venango County (50,328) Bedford County (47,817) Perry County (46,212) Mifflin County (46,064) Huntingdon County (44,590) Union County (44,294) Jefferson County (43,108) Tioga County (40,381) McKean County (40,333) Snyder County (40,317) Susquehanna County (40,006) Warren County (38,911) Clarion County (38,305) Clinton County (37,957) Greene County (35,621) Elk County (29,607) Wyoming County (26,557) Juniata County (24,619) Montour County (18,042) Potter County (16,453) Fulton County (14,501) Forest County (6,965) Sullivan County (5,913) Cameron County (4,330)