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Ancestry refers to the lineage or descent of a person, family, or group, tracing back through generations to identify their origins, heritage, and familial connections. It encompasses the genetic, cultural, and historical ties that link individuals to their forebears, shaping their identity and sense of belonging. Ancestry is a multifaceted concept, intertwining biology, genealogy, history, and culture, and it plays a significant role in how people understand themselves and their place in the world.

At its core, ancestry is rooted in genetics. Each individual inherits a unique combination of DNA from their parents, who in turn inherited their DNA from their own ancestors. This genetic material carries information about physical traits, predispositions to certain health conditions, and even behavioral tendencies. Advances in genetic testing, such as DNA analysis, have made it possible for individuals to trace their biological ancestry with remarkable precision. Companies like 23andMe and AncestryDNA offer services that analyze genetic markers to provide insights into a person's ethnic composition and geographic origins, often revealing surprising connections to distant relatives or previously unknown heritage.

Beyond genetics, ancestry is deeply tied to genealogy, the study of family history and lineage. Genealogical research involves constructing family trees, documenting relationships, and uncovering historical records such as birth certificates, marriage licenses, census data, and immigration documents. This process often reveals stories of migration, resilience, and adaptation, offering a window into the lives of ancestors and the challenges they faced. For many, genealogy is a way to honor their forebears and preserve their legacy for future generations.

Cultural ancestry is another critical dimension, encompassing the traditions, languages, customs, and values passed down through generations. It connects individuals to their ethnic or national heritage, shaping their cultural identity and worldview. For example, someone with Irish ancestry might celebrate St. Patrick's Day, learn traditional Irish dance, or explore the Gaelic language, while someone with Japanese ancestry might practice tea ceremonies, study calligraphy, or observe Obon festivals. Cultural ancestry fosters a sense of continuity and belonging, linking individuals to a broader community with shared experiences and values.

Historical ancestry delves into the broader context of a family's or group's past, including significant events, social conditions, and historical movements that shaped their lives. For instance, the transatlantic slave trade, the Irish Potato Famine, or the Jewish diaspora have profoundly influenced the ancestry of millions of people, leaving lasting imprints on their descendants' identities. Understanding historical ancestry often involves grappling with complex narratives of triumph and tragedy, resilience and oppression, and the interplay of individual and collective experiences.

Ancestry also has a deeply personal and emotional dimension. For many, exploring their ancestry is a journey of self-discovery, offering insights into who they are and where they come from. It can foster a sense of pride, connection, and continuity, as well as a deeper appreciation for the struggles and achievements of those who came before. At the same time, it can raise questions about identity, belonging, and the complexities of heritage, particularly for individuals with mixed or multicultural backgrounds.

In a globalized world, ancestry serves as a bridge between the past and the present, connecting individuals to their roots while also highlighting the interconnectedness of human history. It underscores the diversity and richness of human experience, reminding us that every person's story is part of a larger tapestry woven over centuries. Whether through genetic testing, genealogical research, cultural practices, or historical exploration, ancestry offers a profound way to understand ourselves and our place in the world.

A diversification score measures the diversity of ancestries in the county. As the value appoaches 100, ancestry diversity decreases and therefore increasing the risk of a lack of cultural diversity. The ancestry diversification score for this county is:

Most common ancestry not including "Unknown" is:

 
Ancestry Report Part I
DescriptionTotal Population American Native American Hawaiian Caribbean (Latino) Mexican Central American South American Other Hispanic African American Sub- Saharan Caribbean (Black)

San Francisco County852,4466,2661,6283,0718,48168,59234,70011,88811,23323,87310,9178,564
California (in 000's)39,74948215013836212,8611,4034027011,298462359
National (in 000's)343,25113,8902,21362611,32738,8796,1814,6443,68725,8937,8527,174
Alameda County1,663,83710,8404,07613,11917,864279,29752,36117,57120,55688,70039,47530,136
Contra Costa County1,182,10814,0532,5385,99712,377219,56354,15917,73317,05263,77420,32914,302
San Mateo County752,9618,7679908,3826,150112,50844,01311,97912,8198,2683,3873,195
Marin County258,1544,5115504142,13722,97415,8343,9043,8692,9751,9811,174
 
Per Cent to Total PopulationDiversity
Index
 

San Francisco County9.740.740.190.360.998.054.071.391.322.801.281.00
California14.271.210.380.350.9132.363.531.011.763.261.160.90
National7.834.050.640.183.3011.331.801.351.077.542.292.09
Alameda County8.600.650.240.791.0716.793.151.061.245.332.371.81
Contra Costa County8.571.190.210.511.0518.574.581.501.445.391.721.21
San Mateo County8.551.160.131.110.8214.945.851.591.701.100.450.42
Marin County7.681.750.210.160.838.906.131.511.501.150.770.45
 
Comparisons to State Norms % to Total >= 150% % to Total < 50% 

San Francisco County 60.5750.59104.06109.1624.87115.30137.7874.7685.79110.28111.24
California 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00
National 333.42170.8052.71362.0635.0151.01133.6760.94231.08196.98231.42
Alameda County 53.6864.89227.75117.8051.8889.14104.3470.09163.31204.30200.55
Contra Costa County 97.9556.87146.54114.8857.41129.78148.2181.84165.26148.09133.96
San Mateo County 95.9434.83321.5589.6146.18165.57157.1896.5933.6438.7346.98
Marin County 143.9856.4346.3290.8227.51173.74149.4185.0335.3066.0850.35
 
Comparisons to National Norms % to Total >= 150% % to Total < 50% 

San Francisco County 18.1629.62197.4230.1571.04226.05103.08122.6937.1255.9848.07
California 29.9958.55189.7227.62285.66196.0474.81164.1143.2750.7743.21
National 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00
Alameda County 16.1037.99432.0832.54148.20174.7678.06115.0370.67103.7286.66
Contra Costa County 29.3833.30278.0031.73163.98254.42110.88134.3071.5275.1857.89
San Mateo County 28.7720.39610.0324.75131.92324.60117.59158.5114.5619.6620.30
Marin County 43.1833.0487.8825.0978.57340.60111.78139.5415.2833.5521.76
 
Ancestry Report Part II
DescriptionTotal Population Canadian British Dutch French German Italian Polish Scandi­navian Scotish/ Irish Spanish Other European

San Francisco County852,4461,62021,7141,8927,28022,07114,7875,2238,46829,8063,63726,431
California (in 000's)39,749601,0821102191,1185571734251,133161796
National (in 000's)343,2511,35018,0691,8283,64224,7089,0274,6675,96920,6251,1409,563
Alameda County1,663,8371,46932,9602,9097,40633,63017,7516,03013,93936,8165,29828,905
Contra Costa County1,182,1081,69940,8173,4857,53339,11224,8216,29417,52044,4086,93529,238
San Mateo County752,9611,06220,4241,9255,16920,24016,5773,7578,84024,4242,92418,481
Marin County258,1541,07920,1481,7224,21517,72910,7713,3208,86021,7711,72116,487
 
Per Cent to Total PopulationDiversity
Index
 

San Francisco County9.740.192.550.220.852.591.730.610.993.500.433.10
California14.270.152.720.280.552.811.400.431.072.850.402.00
National7.830.395.260.531.067.202.631.361.746.010.332.79
Alameda County8.600.091.980.170.452.021.070.360.842.210.321.74
Contra Costa County8.570.143.450.290.643.312.100.531.483.760.592.47
San Mateo County8.550.142.710.260.692.692.200.501.173.240.392.45
Marin County7.680.427.800.671.636.874.171.293.438.430.676.39
 
Comparisons to State Norms % to Total >= 150% % to Total < 50% 

San Francisco County 126.0593.5780.45154.9492.06123.76141.1092.98122.65105.46154.77
California 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00
National 260.90193.38193.04192.49255.95187.63313.10162.76210.7882.11139.07
Alameda County 58.5672.7763.3780.7671.8776.1183.4678.4177.6278.7186.72
Contra Costa County 95.33126.84106.86115.61117.65149.80122.62138.72131.78145.01123.46
San Mateo County 93.5599.6492.67124.5595.58157.07114.91109.89113.7995.99122.52
Marin County 277.23286.71241.79296.22244.19297.67296.17321.24295.83164.78318.79
 
Comparisons to National Norms % to Total >= 150% % to Total < 50% 

San Francisco County 48.3148.3941.6880.4935.9765.9645.0757.1358.19128.44111.29
California 38.3351.7151.8051.9539.0753.3031.9461.4447.44121.7971.90
National 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00
Alameda County 22.4537.6332.8341.9528.0840.5726.6648.1836.8395.8662.35
Contra Costa County 36.5465.5955.3660.0645.9679.8439.1685.2362.52176.6188.77
San Mateo County 35.8651.5348.0164.7037.3483.7136.7067.5253.98116.9088.09
Marin County 106.26148.26125.25153.8995.41158.6594.59197.38140.35200.69229.22
 
Ancestry Report Part III
DescriptionTotal Population Chinese Filipino Japanese Korean Vietnamese South Central Asian South East Asian Other Asian Middle Eastern Other Ancestry Unknown

San Francisco County852,446171,22133,5489,76310,58013,93923,25418,14011,1407,283157,48663,950
California (in 000's)39,7491,5551,2622654626619105623554225,9552,889
National (in 000's)343,2514,4613,0107931,5411,9135,4521,6431,2291,93147,32251,000
Alameda County1,663,837175,76687,26311,86919,98632,802147,72337,05923,29111,389259,79795,784
Contra Costa County1,182,10853,43357,3447,9959,82310,88148,60516,95612,60112,807193,60794,317
San Mateo County752,96188,41263,7739,6107,3354,97224,06819,3559,4857,538124,62549,507
Marin County258,1544,3632,5401,5741,4301,3472,2401,3191,0733,30938,13332,680
 
Per Cent to Total PopulationDiversity
Index
 

San Francisco County9.7420.093.941.151.241.642.732.131.310.8518.477.50
California14.273.913.180.671.161.662.291.410.891.0614.987.27
National7.831.300.880.230.450.561.590.480.360.5613.7914.86
Alameda County8.6010.565.240.711.201.978.882.231.400.6815.615.76
Contra Costa County8.574.524.850.680.830.924.111.431.071.0816.387.98
San Mateo County8.5511.748.471.280.970.663.202.571.261.0016.556.57
Marin County7.681.690.980.610.550.520.870.510.421.2814.7712.66
 
Comparisons to State Norms % to Total >= 150% % to Total < 50% 

San Francisco County 513.37123.95171.85106.7198.32119.14150.46146.2280.55123.32103.23
California 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00
National 33.2227.6234.6638.6133.5169.3733.8440.0853.0392.03204.45
Alameda County 270.00165.18107.04103.27118.54387.77157.49156.6364.54104.2379.22
Contra Costa County 115.53152.78101.4871.4455.34179.58101.42119.27102.15109.33109.79
San Mateo County 300.11266.75191.5083.7539.70139.61181.75140.9594.39110.4890.48
Marin County 43.2030.9991.4947.6231.3737.9036.1346.51120.8698.60174.20
 
Comparisons to National Norms % to Total >= 150% % to Total < 50% 

San Francisco County 1,545.50448.74495.83276.39293.42171.75444.60364.87151.90134.0150.49
California 301.05362.04288.53259.02298.45144.16295.49249.53188.56108.6648.91
National 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00
Alameda County 812.83598.01308.83267.50353.76558.99465.36390.83121.70113.2638.75
Contra Costa County 347.80553.12292.80185.05165.17258.87299.69297.62192.62118.8053.70
San Mateo County 903.48965.73552.54216.94118.49201.25537.06351.71177.99120.0644.25
Marin County 130.04112.19263.96123.3693.6354.63106.75116.05227.89107.1485.20


Sources: STI: PopStats, Circa April 2025

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