Southern states, along with a few notable outliers like Alaska and South Dakota, consistently report the highest STD rates in the United States. Based on the CDC’s 2023 surveillance data, Mississippi, Louisiana, South Dakota, Georgia, and Alaska rank near the top across multiple sexually transmitted infections. The pattern is driven largely by limited healthcare access, underfunded sexual health clinics, and concentrated poverty.
States With the Highest Gonorrhea Rates
Gonorrhea is one of the most commonly reported STDs and a useful benchmark for comparing states. The CDC’s 2023 data ranks these five states highest for gonorrhea cases per 100,000 residents:
- Alaska: 310.9 per 100,000
- Louisiana: 288.4 per 100,000
- Georgia: 274.8 per 100,000
- South Dakota: 253.3 per 100,000
- Mississippi: 251.1 per 100,000
Alaska’s top ranking surprises many people, but its remote communities face severe shortages of healthcare providers and testing resources. Rural isolation makes routine screening far less common than in urban areas, which allows infections to spread undetected for longer.
States With the Highest Syphilis Rates
Syphilis has surged across the country in recent years, and the state-level numbers reflect that. The national rate of primary and secondary syphilis in 2023 was 15.8 per 100,000 people. Several states far exceed that average.
South Dakota stands out dramatically, with a rate of 73.4 per 100,000, more than four times the national average. The District of Columbia followed at 39.9, then New Mexico at 36.6, Mississippi at 30.1, and Arkansas at 29.2. Alabama (28.6), Oklahoma (27.7), Montana (27.5), and Louisiana (26.1) also ranked well above the national rate.
On the other end of the spectrum, Vermont reported just 3 cases total in 2023, a rate of 0.5 per 100,000. Wyoming (2.2), Idaho (3.8), and New Hampshire (3.9) also had very low rates. The gap between the highest and lowest states is enormous, with South Dakota’s rate nearly 150 times that of Vermont’s.
The Southern Pattern
Look at any STD ranking and the same region dominates: the Deep South. Mississippi, Louisiana, Alabama, Georgia, Arkansas, and South Carolina appear repeatedly near the top for gonorrhea, chlamydia, and syphilis. This isn’t coincidence. It reflects a cluster of overlapping disadvantages that the CDC groups under “social vulnerability.”
Counties with high social vulnerability tend to have lower incomes, less health insurance coverage, fewer clinics offering STD testing, and larger populations of young people and racial minorities who are disproportionately affected. Many Southern states chose not to expand Medicaid under the Affordable Care Act, leaving large numbers of residents without affordable access to routine screening. When people can’t easily get tested, infections go undiagnosed and continue spreading. At the same time, funding for dedicated STD clinics has declined nationally, and that decline hits hardest in states that already had thin safety nets.
Geography compounds the problem. In rural parts of the South, the nearest clinic offering confidential STD testing might be an hour’s drive away. Stigma around sexual health is also more pronounced in some of these communities, discouraging people from seeking care even when it’s available.
Who Is Most Affected
STD rates are not evenly distributed within any state. Young adults between 15 and 24 account for a disproportionate share of chlamydia and gonorrhea cases nationwide. The CDC recommends annual chlamydia and gonorrhea screening for all sexually active women under 25, but screening rates remain uneven.
Racial disparities are also significant. National longitudinal data shows that by their late twenties, 60% of Black women had received at least one STD diagnosis, compared with 32 to 35% of white and Hispanic women. Among men, 34% of Black men had received an STD diagnosis by their late twenties, versus 12% of white men and 18% of Hispanic men. These gaps reflect differences in healthcare access, neighborhood-level transmission rates, and the tendency for sexual networks to be racially concentrated, meaning that higher background rates in a community increase individual risk regardless of personal behavior.
Men who have sex with men also face elevated risk across all racial groups. In national survey data, gay and bisexual men were 2 to 8 times more likely than heterosexual white men to report an STD diagnosis, with mixed-orientation Black men facing the highest odds.
Why Some States Break the Pattern
Not every high-ranking state fits the Southern mold. South Dakota’s syphilis rate, the highest in the country by a wide margin, is tied to outbreaks concentrated among Native American communities and populations experiencing homelessness, where access to consistent healthcare is extremely limited. Montana, another unexpected entry in the top ten for syphilis, faces similar challenges with rural healthcare access and indigenous health disparities.
Alaska’s consistently high gonorrhea and chlamydia rates reflect its unique geography. Many communities are reachable only by plane, making it difficult to maintain consistent public health services. Testing supplies, treatment, and contact tracing all become more complex when patients live in villages spread across vast distances.
Meanwhile, some large states with major cities rank lower than you might expect. New York’s syphilis rate (14.8) sits below the national average despite the size of New York City, partly because the state has invested heavily in public health infrastructure, widespread testing programs, and outreach to high-risk populations. California (16.3) is only slightly above the national average for similar reasons.
What Drives State-Level Differences
The variation between states comes down to a handful of measurable factors. States with higher STD rates tend to share several characteristics: less Medicaid coverage, fewer sexual health clinics per capita, higher poverty rates, and larger proportions of residents under 25. The CDC’s Social Vulnerability Index captures these overlapping risks across four domains: socioeconomic status, household composition and disability, minority status and language barriers, and housing and transportation access.
Counties that score high on social vulnerability consistently have higher chlamydia and gonorrhea rates. This holds true across the country, but the concentration of high-vulnerability counties in the South explains why that region leads national rankings year after year. State-level policies also matter. States that fund robust STD screening programs, support school-based health education, and expand insurance coverage to low-income residents generally see lower rates, even when their demographics would predict otherwise.