STD Rates in Idaho
CDC surveillance data for Idaho covering chlamydia, gonorrhea, syphilis, and HIV — with 15-year trends, state comparisons, and local testing resources.
Idaho sits near the bottom of national STD rankings — 46th out of 50 states in 2023, with a combined rate of 338.3 cases per 100,000 people. That puts it well below the national median. But the state's recent history is more complicated than a low ranking suggests. Gonorrhea and syphilis both surged for most of the past decade, and though they've pulled back sharply in the last year, neither has returned to where it started.
Chlamydia remains the most common STD in Idaho by a wide margin — 5,793 cases in 2023, at a rate of 294.9 per 100,000. That's well below the national median of 471.3, and the trend has actually been moving in a favorable direction since peaking around 2019. The rate has fallen roughly 23% from that peak, and the most recent year-over-year drop was 4.3%. Idaho has never been a high-chlamydia state, and the numbers are reinforcing that position.
Gonorrhea is where the longer story gets more complicated. Idaho's rate hit a low of 7.1 per 100,000 in 2009, climbed steadily through the 2010s, and peaked at 83.4 in 2019 — more than a tenfold increase in a decade. It's been falling since, and the 2023 rate of 39.6 represents a 30% drop in a single year. Still, that rate is still more than five times what it was in 2009. Syphilis followed a similar arc: it was nearly nonexistent in 2009 at 0.2 per 100,000, climbed to 6.1 by 2022, then fell sharply to 3.8 in 2023 — a 38% decline. Both diseases remain well below the national medians of 152.2 and 14.8, respectively, but the trajectory of the last 15 years is worth understanding even as the numbers improve.
HIV data tells a quieter story. Idaho recorded between 35 and 53 new diagnoses per year between 2017 and 2022 — some of the lowest raw counts of any state in the country. The rate briefly dipped to 2.4 per 100,000 in 2019 and 2020, then rose to 3.4 in 2021 before settling back to 2.7 in 2022; the 2021 uptick likely reflects catch-up diagnoses after pandemic-era testing slowdowns. If you're in Boise, Meridian, or Nampa and haven't been tested recently, STDTest.com can help you find a location near you.
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Free to use on your own site with attribution. Figures are CDC STD Surveillance 2023.
Idaho, 2023: Chlamydia 294.9 per 100,000 (5,793 cases), 37.4% below the US median of 471.3. Gonorrhea 39.6 per 100,000 (778 cases), 74.0% below the US median of 152.2. Syphilis 3.8 per 100,000 (74 cases), 74.3% below the US median of 14.8.
STD Trends in Idaho
Idaho's chlamydia rate has been trending downward since 2019, reaching 294.9 per 100,000 in 2023 — about 37% below the national median of 471.3. The long-run picture is modest: the rate is only about 7% higher than it was in 2008, meaning Idaho never experienced the sustained surge that drove rates up in many other states. The current direction is one of gradual, consistent decline.
Idaho's gonorrhea rate rose more than 1,000% between 2009 and 2019, from 7.1 to 83.4 per 100,000 — one of the sharpest long-run climbs in the state's STD record. It has since come down considerably, dropping 30% in 2023 alone to 39.6. Even so, the current rate is more than five times what it was 15 years ago, and at 39.6, it remains well below the national median of 152.2.
Syphilis in Idaho was nearly invisible in the early 2000s — rates below 1.0 per 100,000 for most of that period — before a sustained rise brought it to 6.1 in 2022. The 2023 drop to 3.8 was the sharpest single-year decline in recent history, a 38% reduction. The rate is still well below the national median of 14.8, but the arc from near-zero to a recent high and back down is the defining feature of Idaho's syphilis story.
Idaho's HIV data covers 2017 through 2022 only — more recent figures aren't yet available in CDC surveillance releases. New diagnoses ranged from 35 to 53 per year across that window, consistently among the lowest counts in the country. The dip in 2019 and 2020 likely reflects reduced testing access during the pandemic rather than a true decline in transmission; the jump to 53 cases in 2021 supports that reading.
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STD Rates by County
County-level data from CDC surveillance. Ranked by combined rate per 100,000.
| County | State Rank | Combined | Chlamydia | Gonorrhea | Syphilis |
|---|---|---|---|---|---|
| Cassia County | #1 of 43 | 544.8 | 513.7 | 31.1 | 0.0 |
| Jerome County | #2 of 43 | 529.8 | 490.6 | 31.4 | 7.8 |
| Minidoka County | #3 of 43 | 489.3 | 462.6 | 17.8 | 8.9 |
| Ada County | #4 of 43 | 466.7 | 400.2 | 62.5 | 4.0 |
| Twin Falls County | #5 of 43 | 428.8 | 386.7 | 38.9 | 3.2 |
| Camas County | #6 of 43 | 405.8 | 405.8 | 0.0 | 0.0 |
| Canyon County | #7 of 43 | 405.6 | 349.7 | 48.5 | 7.4 |
| Elmore County | #8 of 43 | 370.1 | 336.4 | 30.3 | 3.4 |
| Bannock County | #9 of 43 | 364.0 | 314.2 | 46.5 | 3.3 |
| Lewis County | #10 of 43 | 347.7 | 294.2 | 53.5 | 0.0 |
| Lincoln County | #11 of 43 | 311.9 | 275.2 | 36.7 | 0.0 |
| Gooding County | #12 of 43 | 298.9 | 261.5 | 37.4 | 0.0 |
| Latah County | #13 of 43 | 293.0 | 263.9 | 29.1 | 0.0 |
| Kootenai County | #14 of 43 | 282.1 | 229.7 | 45.4 | 7.0 |
| Blaine County | #15 of 43 | 267.6 | 255.6 | 8.0 | 4.0 |
| Butte County | #16 of 43 | 253.8 | 253.8 | 0.0 | 0.0 |
| Teton County | #17 of 43 | 247.0 | 223.1 | 23.9 | 0.0 |
| Bonneville County | #18 of 43 | 239.8 | 220.0 | 18.3 | 1.5 |
| Bingham County | #19 of 43 | 232.1 | 210.3 | 19.8 | 2.0 |
| Adams County | #20 of 43 | 224.4 | 224.4 | 0.0 | 0.0 |
| Washington County | #21 of 43 | 218.8 | 201.3 | 17.5 | 0.0 |
| Payette County | #22 of 43 | 212.7 | 176.0 | 36.7 | 0.0 |
| Benewah County | #23 of 43 | 212.1 | 183.2 | 28.9 | 0.0 |
| Owyhee County | #24 of 43 | 204.4 | 165.1 | 31.4 | 7.9 |
| Nez Perce County | #25 of 43 | 202.4 | 197.7 | 4.7 | 0.0 |
| Gem County | #26 of 43 | 199.3 | 180.3 | 19.0 | 0.0 |
| Valley County | #27 of 43 | 189.8 | 166.1 | 23.7 | 0.0 |
| Boise County | #28 of 43 | 187.8 | 152.6 | 35.2 | 0.0 |
| Clearwater County | #29 of 43 | 173.6 | 173.6 | 0.0 | 0.0 |
| Shoshone County | #30 of 43 | 171.1 | 135.5 | 28.5 | 7.1 |
| Boundary County | #31 of 43 | 169.7 | 154.9 | 14.8 | 0.0 |
| Power County | #32 of 43 | 169.6 | 169.6 | 0.0 | 0.0 |
| Franklin County | #33 of 43 | 154.9 | 122.6 | 25.8 | 6.5 |
| Bonner County | #34 of 43 | 148.4 | 121.8 | 22.8 | 3.8 |
| Lemhi County | #35 of 43 | 142.1 | 130.3 | 11.8 | 0.0 |
| Oneida County | #36 of 43 | 141.3 | 141.3 | 0.0 | 0.0 |
| Caribou County | #37 of 43 | 124.7 | 110.8 | 13.9 | 0.0 |
| Jefferson County | #38 of 43 | 117.0 | 108.2 | 8.8 | 0.0 |
| Custer County | #39 of 43 | 110.5 | 88.4 | 22.1 | 0.0 |
| Fremont County | #40 of 43 | 105.7 | 91.6 | 14.1 | 0.0 |
| Bear Lake County | #41 of 43 | 103.5 | 103.5 | 0.0 | 0.0 |
| Madison County | #42 of 43 | 99.0 | 80.7 | 16.5 | 1.8 |
| Idaho County | #43 of 43 | 89.5 | 78.3 | 11.2 | 0.0 |
What the numbers mean — and what to do about them
Idaho's combined STD rate of 338.3 per 100,000 translates to roughly 6,645 total diagnoses across chlamydia, gonorrhea, and syphilis in 2023 — in a state of just under two million people. That places Idaho among the five lowest-burden states in the country. But those numbers only reflect reported, diagnosed cases. Chlamydia and gonorrhea are both frequently asymptomatic, and Idaho's historically low testing rates relative to high-burden states may mean some infections go undetected and unreported.
The trend that matters most clinically is gonorrhea. Even with the sharp 2023 decline, Idaho's gonorrhea rate is more than five times what it was in 2009. Gonorrhea can cause serious reproductive complications if left untreated, and asymptomatic infections are common — meaning people can transmit the disease for months without any signs. The same applies to chlamydia, which accounts for the vast majority of Idaho's STD caseload. Neither disease announces itself reliably, which is why testing is the only way to know.
If you live in Boise, Meridian, or Nampa, routine testing is straightforward and widely available. Annual screening is a reasonable baseline for sexually active adults; more frequent testing makes sense if you have new or multiple partners. Idaho's overall numbers are low by national standards, but the gonorrhea surge of the past decade happened quietly — rates multiplied while most people had no reason to think the risk had changed. STDTest.com can show you where to get tested in your zip code today.
WHO SHOULD GET TESTED
Sexually active adults under 25 face the highest chlamydia risk — that holds in Idaho as it does nationally. Given Idaho's gonorrhea rate is still more than five times its 2009 baseline, anyone with new or multiple partners should include gonorrhea in their panel. Men who have sex with men face elevated risk for all three bacterial STDs and should discuss regular syphilis screening with a provider.
HOW OFTEN
Once a year is a reasonable starting point for most sexually active adults in Idaho. Given that both chlamydia and gonorrhea are routinely asymptomatic, annual testing is the only reliable way to catch infections before they cause complications or spread. If your partner count or situation changes, testing every three to six months is appropriate.
WHAT TO EXPECT
Most STD tests involve a urine sample, a swab, or a blood draw — often a combination depending on the panel. Results typically come back within a few days. Many clinics in the Boise area offer confidential testing without requiring a referral, and some offer same-day appointments. The process is quick, private, and far less complicated than most people expect.
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