There are currently about 110 million people in the U.S. living with a sexually-transmitted disease (STD), also known as an STI, or sexually-transmitted infection. But which parts of the U.S. are more likely to have higher rates of STDs?

According to a “Heat Map” based on data from 2010 and 2012 Centers for Disease Control & Prevention studies, it’s the Southeast . The rates in states like Louisiana, Mississippi, Arkansas, and Alabama are much higher than in the rest of the country when it comes to chlamydia, gonorrhea, and syphilis — although AIDS in particular is more prevalent in the Northeast.

Chlamydia is one of the most frequently recorded STDs in the U.S.; over one million cases have been reported, with the majority occurring in southeastern states. The CDC also found that one in 15 sexually active girls — between the young ages of 14 and 19 — have chlamydia. According to the CDC, up to 20 million new STD infections occur every year — these include hepatitis B, HIV, syphilis, gonorrhea, HPV, and chlamydia. Half of these new infections are among young people between the ages of 15 and 24. So the prevalence among young people is quite high in these “hotspots.”

“STIs take a big health and economic toll on men and women in the United States, especially our youth,” CDC epidemiologist Dr. Catherine Lindsey Satterwhite told NBC News.

Gonorrhea is most prevalent in the South, followed by the Midwest, Northeast, and West. The state with the highest gonorrhea rate per 100,000 people is Mississippi (209.9 people per 100,000), followed by Louisiana, South Carolina, and Alabama.

AIDS, though it remains high in the southeast as well, is even higher in the Northeast, with Maryland and New York having the highest rates per 100,000 people — at 22.1 and 20.6, respectively. Mississippi, Alabama, and Louisiana also have the most obese populations. “The Bible Belt is trending in an unholy way,” EDU in Review writes. “[T]he STD numbers in the [southeastern] states are high enough to be classified as epidemic.”

It’s possible that lack of contraception use in these states is one of the factors behind the STD rates — the South is known for its religious tendencies and believing that using condoms is unholy. Proper medical care may be more difficult to reach in rural areas. The South is also filled with colleges — and sex-driven, impulsive, and careless college students, the young people who make up a pretty solid number of the new infections every year.

What makes STDs so tricky is the fact that their symptoms are often subtle or nonexistent, so people — and especially young people — may go weeks or months without knowing they have been infected. If diagnosed and treated early, trichomoniasis, gonorrhea, chlamydia, and syphilis can be cured, but if they are left untreated, they can lead to serious health consequences, the CDC says. Undiagnosed and untreated chlamydia or gonorrhea may cause chronic pelvic pain in women, as well as ectopic pregnancy. It may also increase the chances of infertility among women. So before travelling to the South — or anywhere, really — keep in mind that condom use is one of the most effective ways to prevent STDs, and be sure that you and your partner are both tested before taking part in sexual activity.