STD Rates in Marin County, California

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

Data Year: 2023 Source: CDC STI Surveillance Population: 254,416
Combined
396.6
per 100K
39th / 58
Chlamydia
294.4
per 100K • 749 cases
US rate: 490.7
38th of 58 in California
Higher than 52% of US counties
Gonorrhea
97.1
per 100K • 247 cases
US rate: 178.2
29th of 58 in California
Higher than 64% of US counties
Syphilis P&S
5.1
per 100K • 13 cases
Based on 13 cases — interpret with care
US rate: 15.8

Marin County recorded a combined STD rate of 396.6 per 100,000 residents in 2023, ranking 39th of 58 counties in California. Reported infections included chlamydia at 294.4 per 100,000 (749 cases, 40% below the state rate), gonorrhea at 97.1 per 100,000 (247 cases, 49% below the state rate), syphilis at 5.1 per 100,000 (13 cases, too few for a reliable comparison). Confidential STD testing is available throughout Marin County — knowing your status is the only way to catch infections that often show no symptoms.

STD Trends in Marin 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
294.4
per 100K in 2023
0.0 in 2000
Peak 357.0 in 2019
Gonorrhea
97.1
per 100K in 2023
0.0 in 2000
Peak 97.1 in 2023
Syphilis (P&S)
5.1
per 100K in 2023
0.4 in 2000
Peak 8.1 in 2021

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

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Marin County vs California and the US

Infection Marin County California US vs California vs US Rank in California
Chlamydia 294.4749 cases 491.1 490.7 40.1% below 40% below 38th of 58
Gonorrhea 97.1247 cases 190.2 178.2 48.9% below 45.5% below 29th of 58
Syphilis (P&S) 5.113 cases 16.3 15.8 Too few cases Too few cases –

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

Marin County ranks 39th of 58 California counties for combined STD rate in 2023, at 396.6 per 100,000 residents.
In 2023, chlamydia was the most frequently reported STD in Marin County, with 749 cases at a rate of 294.4 per 100,000 residents.
STDTest.com lists confidential testing locations across Marin 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.