Data / Rankings / Current asthma in adults, local model estimate / Counties in California

Counties in California by current asthma in adults, local model estimate

Humboldt County had the highest current asthma in adults, local model estimate of 58 counties in 2021, at 10.7%. Santa Clara County had the lowest, at 7.9%. The median was 9.8%. Source: the Centers for Disease Control and Prevention.

Highest10.7Humboldt County
Lowest7.9Santa Clara County
Median9.858 counties

All counties, 2021

Humboldt County: 10.7 %Humboldt County10.7Madera County: 10.6 %Madera County10.6Lake County: 10.5 %Lake County10.5Tehama County: 10.5 %Tehama County10.5Del Norte County: 10.4 %Del Norte County10.4Modoc County: 10.4 %Modoc County10.4Siskiyou County: 10.4 %Siskiyou County10.4Trinity County: 10.4 %Trinity County10.4Yuba County: 10.4 %Yuba County10.4Butte County: 10.3 %Butte County10.3Tulare County: 10.3 %Tulare County10.3Glenn County: 10.2 %Glenn County10.2Kern County: 10.2 %Kern County10.2Merced County: 10.2 %Merced County10.2Shasta County: 10.2 %Shasta County10.2Stanislaus County: 10.2 %Stanislaus County10.2Mendocino County: 10.1 %Mendocino County10.1Colusa County: 10 %Colusa County10Kings County: 10 %Kings County10Calaveras County: 9.9 %Calaveras County9.9Fresno County: 9.9 %Fresno County9.9Imperial County: 9.9 %Imperial County9.9Mariposa County: 9.9 %Mariposa County9.9Plumas County: 9.9 %Plumas County9.9Sacramento County: 9.9 %Sacramento County9.9Sutter County: 9.9 %Sutter County9.9Alpine County: 9.8 %Alpine County9.8Lassen County: 9.8 %Lassen County9.8Santa Barbara County: 9.8 %Santa Barbara County9.8Yolo County: 9.8 %Yolo County9.8San Joaquin County: 9.7 %San Joaquin County9.7San Luis Obispo County: 9.7 %San Luis Obispo County9.7Inyo County: 9.6 %Inyo County9.6San Bernardino County: 9.6 %San Bernardino County9.6Sonoma County: 9.6 %Sonoma County9.6Tuolumne County: 9.6 %Tuolumne County9.6El Dorado County: 9.5 %El Dorado County9.5Mono County: 9.5 %Mono County9.5Monterey County: 9.5 %Monterey County9.5Nevada County: 9.5 %Nevada County9.5Santa Cruz County: 9.5 %Santa Cruz County9.5Sierra County: 9.5 %Sierra County9.5Solano County: 9.5 %Solano County9.5Amador County: 9.4 %Amador County9.4Placer County: 9.3 %Placer County9.3San Benito County: 9.3 %San Benito County9.3Los Angeles County: 9.2 %Los Angeles County9.2Napa County: 9.2 %Napa County9.2San Diego County: 9.2 %San Diego County9.2Ventura County: 9.2 %Ventura County9.2Riverside County: 9.1 %Riverside County9.1Contra Costa County: 9 %Contra Costa County9Marin County: 9 %Marin County9Alameda County: 8.6 %Alameda County8.6Orange County: 8.6 %Orange County8.6San Francisco County: 8.2 %San Francisco County8.2San Mateo County: 8 %San Mateo County8Santa Clara County: 7.9 %Santa Clara County7.9
%. Source: CDC, PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence. Retrieved 2026-10-12.

Full ranking

RankCounties2021 (%)
1Humboldt County10.7
2Madera County10.6
3Lake County10.5
3Tehama County10.5
5Del Norte County10.4
5Modoc County10.4
5Siskiyou County10.4
5Trinity County10.4
5Yuba County10.4
10Butte County10.3
10Tulare County10.3
12Glenn County10.2
12Kern County10.2
12Merced County10.2
12Shasta County10.2
12Stanislaus County10.2
17Mendocino County10.1
18Colusa County10
18Kings County10
20Calaveras County9.9
20Fresno County9.9
20Imperial County9.9
20Mariposa County9.9
20Plumas County9.9
20Sacramento County9.9
20Sutter County9.9
27Alpine County9.8
27Lassen County9.8
27Santa Barbara County9.8
27Yolo County9.8
31San Joaquin County9.7
31San Luis Obispo County9.7
33Inyo County9.6
33San Bernardino County9.6
33Sonoma County9.6
33Tuolumne County9.6
37El Dorado County9.5
37Mono County9.5
37Monterey County9.5
37Nevada County9.5
37Santa Cruz County9.5
37Sierra County9.5
37Solano County9.5
44Amador County9.4
45Placer County9.3
45San Benito County9.3
47Los Angeles County9.2
47Napa County9.2
47San Diego County9.2
47Ventura County9.2
51Riverside County9.1
52Contra Costa County9
52Marin County9
54Alameda County8.6
54Orange County8.6
56San Francisco County8.2
57San Mateo County8
58Santa Clara County7.9

Other periods

About this ranking

Percentage of adults who have ever been told by a doctor, nurse or other health professional that they have asthma and say they still have it. Model-based estimate for adults aged 18 and over from CDC PLACES. Crude prevalence, not age-adjusted.

US counties and cities (incorporated places of 10,000 or more). CDC PLACES combines Behavioral Risk Factor Surveillance System (BRFSS) answers with local population data through multilevel regression and poststratification, so a county or city value is a model estimate, not a survey count. The year is the BRFSS survey year, not the release year. CDC says the method does not support tracking change in a place over time, and each annual release can change the model, so values for different years are not strictly comparable. A state is missing in a year when its BRFSS data did not meet standards (Kentucky and Pennsylvania in 2023, Florida in 2021). Connecticut counties appear as its nine planning regions from 2022; its eight former counties are not served. City values for 2021 come from the 2023 release, built on 2010 Census place boundaries; later years use 2020 boundaries.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

Centers for Disease Control and Prevention (CDC). PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence. https://www.cdc.gov/places/. Retrieved 2026-10-12. These data are available free from CDC. Use does not imply endorsement by CDC, ATSDR, HHS or the United States Government.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

Centers for Disease Control and Prevention. (2025). PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence (Counties in California by current asthma in adults, local model estimate, 2021) [Data set]. Retrieved October 12, 2026, from https://www.cdc.gov/places/

MLA 9

PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence, Counties in California by current asthma in adults, local model estimate, 2021. Centers for Disease Control and Prevention, 4 Dec. 2025, https://www.cdc.gov/places/. Invokely, https://invokely.ai/rankings/adult-asthma-rate-county-estimate/california-counties?period=2021. Accessed 12 Oct. 2026.

Chicago (author-date)

Centers for Disease Control and Prevention. 2025. PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence. Counties in California by current asthma in adults, local model estimate, 2021. Dataset. Accessed October 12, 2026. https://www.cdc.gov/places/. Also distributed by Invokely, https://invokely.ai/rankings/adult-asthma-rate-county-estimate/california-counties?period=2021.

Harvard

Centers for Disease Control and Prevention (2025) PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence, Counties in California by current asthma in adults, local model estimate, 2021 [Dataset]. Available at: https://www.cdc.gov/places/, via Invokely: https://invokely.ai/rankings/adult-asthma-rate-county-estimate/california-counties?period=2021 (Accessed: 12 October 2026).

BibTeX
@misc{centers_counties_in_california_by_2021,
  author = {{Centers for Disease Control and Prevention}},
  title = {{PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence: Counties in California by current asthma in adults, local model estimate, 2021}},
  year = {2025},
  howpublished = {Data set},
  url = {https://www.cdc.gov/places/},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/adult-asthma-rate-county-estimate/california-counties?period=2021. Publisher attribution: Centers for Disease Control and Prevention (CDC). PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence. https://www.cdc.gov/places/. Retrieved 2026-10-12. These data are available free from CDC. Use does not imply endorsement by CDC, ATSDR, HHS or the United States Government.},
}
RIS
TY  - DATA
AU  - Centers for Disease Control and Prevention
TI  - PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence: Counties in California by current asthma in adults, local model estimate, 2021
PY  - 2025
DA  - 2025/12/04
PB  - Centers for Disease Control and Prevention
DB  - Invokely
UR  - https://www.cdc.gov/places/
L2  - https://invokely.ai/rankings/adult-asthma-rate-county-estimate/california-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/adult-asthma-rate-county-estimate/california-counties?period=2021.
N1  - Publisher attribution: Centers for Disease Control and Prevention (CDC). PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence. https://www.cdc.gov/places/. Retrieved 2026-10-12. These data are available free from CDC. Use does not imply endorsement by CDC, ATSDR, HHS or the United States Government.
ER  -
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Rank Counties in California by current asthma in adults, local model estimate using official data, and cite the source.
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Questions

Which county has the highest current asthma in adults, local model estimate?

Humboldt County, with 10.7% in 2021, according to the Centers for Disease Control and Prevention.

Which county has the lowest current asthma in adults, local model estimate?

Santa Clara County, with 7.9% in 2021.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: Centers for Disease Control and Prevention, PLACES: Local Data for Better Health, County Data (swc5-untb, fu4u-a9bh, h3ej-a9ec and later releases), current asthma in adults, crude prevalence. Retrieved 2026-10-12.

Current asthma in adults, local model estimate: other rankings

Counties in California: more rankings