STD Rates in Williamson County, Illinois

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

Get Tested Now Find a Clinic
Data Year: 2023 Source: CDC STI Surveillance Population: 66,714
Combined
581.6
per 100K
21st / 102
Chlamydia
424.2
per 100K • 283 cases
Gonorrhea
133.4
per 100K • 89 cases
Syphilis P&S
24
per 100K • 16 cases

Williamson County has one of the higher STD burdens in Illinois, with a combined rate of 581.6 per 100,000 residents in 2023 — ranking 21st of 102 counties. Reported infections included chlamydia at 424.2 per 100,000 (283 cases, 24% below the state rate), gonorrhea at 133.4 per 100,000 (89 cases, 34% below the state rate), syphilis at 24.0 per 100,000 (16 cases, 107% above the state rate). Confidential STD testing is available throughout Williamson County — knowing your status is the only way to catch infections that often show no symptoms.

Know your status — get tested today

Same-day testing at 4,500+ locations. No appointment needed. Results in 1–3 days.

Compare Tests & Pricing Find a clinic

Williamson County vs Illinois Average

Infection Williamson County Illinois Rate Difference
Chlamydia 424.2 557.7 24% below
Gonorrhea 133.4 202.3 34% below
Syphilis (P&S) 24 11.6 107% above

Find a clinic near you

4,500+ testing locations nationwide. 100% confidential. Most insurance accepted.

Compare Tests & Pricing Find a clinic

Largest cities in Williamson County, Illinois

Largest first, by Census population. Each city page lists nearby clinics, free and low-cost testing, and labs.

STD testing in Marion, IL16,836 people → STD testing in Herrin, IL12,226 people → STD testing in Carterville, IL5,818 people →

Largest Counties in Illinois

Cook County → Dupage County → Lake County → Will County → Kane County → Mchenry County → Winnebago County → Madison County → St. Clair County → Champaign County →

All 102 Illinois counties → STD testing in Illinois →

FAQs

Williamson County ranks 21st of 102 Illinois counties for combined STD rate in 2023, at 581.6 per 100,000 residents.
In 2023, chlamydia was the most frequently reported STD in Williamson County, with 283 cases at a rate of 424.2 per 100,000 residents.
STDTest.com lists confidential testing locations across Williamson County and Illinois. Many offer same-day appointments with results in 1–3 days.

Related Resources

STD Testing Window Periods How Soon After Sex to Test STD Symptoms Guide Testing Timeline Chart All Testing Clinics STD Statistics and Data
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.
Sources