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San Francisco Bay Area Households, Household Population, and Average Household Size: 1930-2000

Total Households by Bay Area County
County 1930 1940 1950 1960 1970 1980 1990 2000
San Francisco 178,625 206,011 257,734 291,975 295,174 298,956 305,584 329,700
San Mateo 20,793 33,516 71,448 135,179 185,028 225,201 241,914 254,103
Santa Clara 40,169 51,916 85,424 184,945 322,782 458,519 520,180 565,863
Alameda 137,090 165,201 238,087 295,367 365,093 426,092 479,518 523,366
Contra Costa 20,717 29,830 83,371 117,858 172,951 241,534 300,288 344,129
Solano 10,909 14,559 30,449 38,453 51,120 80,426 113,429 130,403
Napa 5,709 7,679 12,652 18,867 25,098 36,624 41,312 45,402
Sonoma 18,151 21,641 32,947 47,191 67,861 114,474 149,011 172,403
Marin 10,568 13,576 25,208 44,209 67,266 88,723 95,006 100,650
Region 442,731 543,929 837,320 1,174,044 1,552,373 1,970,549 2,246,242 2,466,019
Total Household Population, by Bay Area County
County 1930 1940 1950 1960 1970 1980 1990 2000
San Francisco 634,394 634,536 698,176 711,222 689,337 654,511 699,330 756,976
San Mateo 77,405 111,782 227,920 437,705 548,513 580,517 637,628 696,711
Santa Clara 145,118 174,949 272,536 621,610 1,039,685 1,267,671 1,463,219 1,652,871
Alameda 474,883 513,011 702,979 875,899 1,036,706 1,077,339 1,242,068 1,416,006
Contra Costa 78,608 100,450 279,546 404,230 550,717 649,595 793,585 937,479
Solano 40,834 49,118 96,021 125,389 160,344 226,954 326,662 378,568
Napa 22,897 28,503 38,895 57,996 73,212 93,361 105,085 119,046
Sonoma 62,222 69,052 96,717 142,247 198,078 293,392 380,558 447,512
Marin 41,648 52,907 75,668 139,188 197,645 215,273 221,548 235,803
Region 1,578,009 1,734,308 2,488,458 3,515,486 4,494,237 5,058,613 5,869,683 6,640,972
Average Household Size, by Bay Area County
County 1930 1940 1950 1960 1970 1980 1990 2000
San Francisco 3.55 3.08 2.71 2.44 2.34 2.19 2.29 2.30
San Mateo 3.72 3.34 3.19 3.24 2.96 2.58 2.64 2.74
Santa Clara 3.61 3.37 3.19 3.36 3.22 2.76 2.81 2.92
Alameda 3.46 3.11 2.95 2.97 2.84 2.53 2.59 2.71
Contra Costa 3.79 3.37 3.35 3.43 3.18 2.69 2.64 2.72
Solano 3.74 3.37 3.15 3.26 3.14 2.82 2.88 2.90
Napa 4.01 3.71 3.07 3.07 2.92 2.55 2.54 2.62
Sonoma 3.43 3.19 2.94 3.01 2.92 2.56 2.55 2.60
Marin 3.94 3.90 3.00 3.15 2.94 2.43 2.33 2.34
Region 3.56 3.19 2.97 2.99 2.90 2.57 2.61 2.69
Source: Data is from the decennial censuses conducted by the US Department of Commerce, Bureau of the Census (www.census.gov). Data analysis is by MTC.
Important Note: Data on households was first collected in the 1940 Decennial Census. Data for 1930 is for families. By definition, families exclude single person households and households of unrelated individuals.