GeoID	Name	1930 Total Population	1940 Total Population	1950 Total Population	1960 Total Population	1970 Total Population	1980 Total Population	1990 Total Population	2000 Total Population	2010 Total Population	2020 Total Population
05000US42003	Allegheny County	1,374,410	1,411,539	1,515,237	1,629,821	1,605,133	1,450,195	1,336,449	1,281,666	1,223,348	1,250,578
05000US42005	Armstrong County	79,298	81,087	80,842	79,524	75,590	77,768	73,478	72,392	68,941	65,558
05000US42007	Beaver County	149,062	156,754	175,192	206,948	208,418	204,441	186,093	181,412	170,539	168,215
05000US42019	Butler County	80,480	87,590	97,320	114,639	127,941	147,912	152,013	174,083	183,862	193,763
05000US42051	Fayette County	198,542	200,999	189,899	169,340	154,667	159,417	145,351	148,644	136,606	128,804
05000US42059	Greene County	41,767	44,671	45,394	39,424	36,090	40,476	39,550	40,672	38,686	35,954
05000US42063	Indiana County	75,395	79,854	77,106	75,366	79,451	92,281	89,994	89,605	88,880	83,246
05000US42073	Lawrence County	97,258	96,877	105,120	112,965	107,374	107,150	96,246	94,643	91,108	86,070
05000US42125	Washington County	204,802	210,852	209,628	217,271	210,876	217,074	204,584	202,897	207,820	209,349
05000US42129	Westmoreland County	288,755	303,411	313,179	352,629	376,935	392,184	370,321	369,993	365,169	354,663
04000US42SPC	SPC Region	2,589,769	2,673,634	2,808,917	2,997,927	2,982,475	2,888,898	2,694,079	2,656,007	2,574,959	2,576,200