STD Rates in Mendocino County, California

2023 CDC surveillance data for Mendocino County, California — chlamydia, gonorrhea, and syphilis rates with state comparisons.

Data Year: 2023 Source: CDC STI Surveillance Population: 89,099
Combined
404
per 100K
36th / 58
Chlamydia
306.4
per 100K • 273 cases
US rate: 490.7
35th of 58 in California
Higher than 54% of US counties
Gonorrhea
67.3
per 100K • 60 cases
US rate: 178.2
40th of 58 in California
Higher than 51% of US counties
Syphilis P&S
30.3
per 100K • 27 cases
US rate: 15.8
5th of 58 in California
Higher than 89% of US counties

Mendocino County recorded a combined STD rate of 404.0 per 100,000 residents in 2023, ranking 36th of 58 counties in California. Reported infections included chlamydia at 306.4 per 100,000 (273 cases, 38% below the state rate), gonorrhea at 67.3 per 100,000 (60 cases, 65% below the state rate), syphilis at 30.3 per 100,000 (27 cases, 86% above the state rate). Confidential STD testing is available throughout Mendocino County — knowing your status is the only way to catch infections that often show no symptoms.

STD Trends in Mendocino County, 2000–2023

Reported cases per 100,000 residents each year, against the California rate (dashed). In a county this size a handful of cases moves the rate a long way, so read the shape rather than any single year.

Chlamydia
306.4
per 100K in 2023
0.0 in 2000
Peak 497.7 in 2018
Gonorrhea
67.3
per 100K in 2023
0.0 in 2000
Peak 241.0 in 2021
Syphilis (P&S)
30.3
per 100K in 2023
0.0 in 2000
Peak 30.3 in 2023

Source: CDC NCHHSTP AtlasPlus county surveillance, 2000–2023.

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Mendocino County vs California and the US

Infection Mendocino County California US vs California vs US Rank in California
Chlamydia 306.4273 cases 491.1 490.7 37.6% below 37.6% below 35th of 58
Gonorrhea 67.360 cases 190.2 178.2 64.6% below 62.2% below 40th of 58
Syphilis (P&S) 30.327 cases 16.3 15.8 85.9% above 91.8% above 5th of 58

Rates per 100,000 residents, 2023. Ranks run from the highest rate (1st) among California’s counties. The US rate is all 50 states combined. Comparisons are left out where fewer than 20 cases were reported, because a rate built on so few cases can swing widely from one year to the next.

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FAQs

Mendocino County ranks 36th of 58 California counties for combined STD rate in 2023, at 404.0 per 100,000 residents.
In 2023, chlamydia was the most frequently reported STD in Mendocino County, with 273 cases at a rate of 306.4 per 100,000 residents.
STDTest.com lists confidential testing locations across Mendocino County and California. Many offer same-day appointments with results in 1–3 days.
Data sourced from the CDC's annual STI Surveillance Report. Rates are per 100,000 population and reflect reported cases only — actual prevalence is likely higher due to undiagnosed infections. While we strive for accuracy, STDTest.com makes no representations or warranties regarding the completeness or accuracy of this data and is not responsible for any errors or omissions. This page is for informational purposes only and does not constitute medical advice.