San Andreas (Californio Spanish for "St. Andrew") is an unincorporated census-designated place in and the county seat of Calaveras County, California. The population was 2,994 at the 2020 census, up from 2,783 at the 2010 census. Like most towns in the region, it was founded during the California Gold Rush. The town is located on State Route 49 and is registered as California Historical Landmark #252.
History
thumb|left|Old Calaveras County Courthouse, built 1867, served in that role for 100 years. Afterwards, it was turned into the Calaveras County Museum, and was listed on the [[National Register of Historic Places (NRHP).]]
Settled by Mexican gold miners in 1848 and named after the Catholic parish St. Andrew, the town has been a noted mining camp since early days. It existed as a tent city for the first few years, and even included a tent church.
In August 1852, a nugget of gold was found here and was sold to Wells Fargo & Co. for US$12,000.
Geography
According to the United States Census Bureau, the CDP has a total area of , of which, 99.81% is land and 0.19% is water.
Climate
San Andreas has a Mediterranean climate typical of the Sierra Nevada foothills. Winters are cool and wet with mild days, chilly nights, and substantial rainfall. Summers are hot and dry with very hot days, cool nights, and minimal rainfall. Due to the orographic effect, rainfall in all seasons is significantly greater than on the valley floor to the west.
Demographics
Racial and ethnic composition
{| class="wikitable sortable" style="text-align:center;"
|+San Andreas CDP, California – Racial and ethnic composition<br><small></small>
!Race / Ethnicity <small>(NH = Non-Hispanic)</small>
!Pop 2000
!Pop 2010
!style="background-color: #ffffb3;" |Pop 2020
!% 2000
!% 2010
!style="background-color: #ffffb3;" |% 2020
|-
|White alone (NH)
|2,310
|2,330
|style='background: #ffffe6; |2,270
|88.34%
|83.72%
|style='background: #ffffe6; |75.82%
|-
|Black or African American alone (NH)
|2
|17
|style='background: #ffffe6; |26
|0.08%
|0.61%
|style='background: #ffffe6; |0.87%
|-
|Native American or Alaska Native alone (NH)
|35
|36
|style='background: #ffffe6; |39
|1.34%
|1.29%
|style='background: #ffffe6; |1.30%
|-
|Asian alone (NH)
|19
|27
|style='background: #ffffe6; |53
|0.73%
|0.97%
|style='background: #ffffe6; |1.77%
|-
|Native Hawaiian or Pacific Islander alone (NH)
|0
|1
|style='background: #ffffe6; |6
|0.00%
|0.04%
|style='background: #ffffe6; |0.20%
|-
|Other race alone (NH)
|7
|0
|style='background: #ffffe6; |26
|0.27%
|0.00%
|style='background: #ffffe6; |0.87%
|-
|Mixed race or Multiracial (NH)
|76
|117
|style='background: #ffffe6; |210
|2.91%
|4.20%
|style='background: #ffffe6; |7.01%
|-
|Hispanic or Latino (any race)
|166
|255
|style='background: #ffffe6; |364
|6.35%
|9.16%
|style='background: #ffffe6; |12.16%
|-
|Total
|2,615
|2,783
|style='background: #ffffe6; |2,994
|100.00%
|100.00%
|style='background: #ffffe6; |100.00%
|}
2020 census
As of the 2020 census, San Andreas had a population of 2,994 and a population density of . The median age was 46.2 years.
For every 100 females, there were 97.5 males; for every 100 females age 18 and over, there were 98.3 males age 18 and over. The age distribution was 20.2% under age 18, 5.9% from 18 to 24, 22.6% from 25 to 44, 25.6% from 45 to 64, and 25.7% age 65 or older.
There were 1,172 households, of which 24.7% included children under age 18. Of all households, 37.3% were married-couple households, 8.6% were cohabiting couple households, 34.9% had a female householder with no partner present, and 19.2% had a male householder with no partner present. About 33.7% of households were one person, and 20.0% were one person aged 65 or older. The average household size was 2.36, and there were 671 families (57.3% of all households).
There were 1,296 housing units at an average density of . Of all housing units, 9.6% were vacant. Of the 1,172 occupied units, 59.0% were owner-occupied and 41.0% were renter-occupied. The homeowner vacancy rate was 3.5%, and the rental vacancy rate was 7.0%. and . Federally, San Andreas is in .