Lyme disease risk is highest this year across the Northeast, mid-Atlantic, and upper Midwest, with pockets of risk along the Pacific coast. Tick activity is running high, and nymphs are out in force. This guide covers which states and regions carry the highest risk right now, plus how to help protect yourself, your yard, and your pets during tick season.
Which states are high risk areas for lyme disease
About 90% of Lyme disease cases in the United States are reported from high-incidence areas in the Northeast, mid-Atlantic, and upper Midwest. The Pacific coast has pockets of risk, but the heaviest concentration stays in those three regions. States with most Lyme disease cases cluster there – New York, Pennsylvania, and New Jersey alone accounted for nearly half of all cases nationwide from 2019 to 2022.
Other states with consistently high Lyme disease activity include:
- Massachusetts, Vermont, and Connecticut (where Lyme disease was first identified)
- Maryland
- Wisconsin, Minnesota, and Michigan – the core of the upper Midwest hotspot
- Northern California and Oregon, where the western blacklegged tick carries the disease along parts of the Pacific coast
National surveillance has documented a steady increase in both incidence and geographic range since 1991. Lyme disease cases have climbed, though it’s worth noting that a sharp jump in 2022 partly reflects a change in how cases are counted rather than a true rise in risk. The consistent trend across three decades of data is that blacklegged ticks keep expanding into new territory.
This year, that expansion meets unusually high tick activity. Across most of the country, emergency room visits for tick bites are at their highest level for this time of year since 2017. Tick-bite ER visits in April 2026 rose more than 25% over April 2025, climbing to roughly 104 per 100,000 total ER visits from 68.
“Currently, it appears that tick nymphs in northern populations may exhibit more pronounced host-seeking behavior, resulting in more direct interactions with humans and a corresponding rise in Lyme disease cases,” said Isaac Rockwell, Aptive’s in-house entomologist. “Those northern populations appear to be expanding southward into areas where blacklegged ticks already exist, but where populations may have previously exhibited less pronounced host-seeking behavior.”
Why tick risk is surging this summer
While ticks are most active from April through September, the highest risk of tick bites occurs during the late spring and summer when nymphal blacklegged ticks are most active. These nymphs are about the size of a poppy seed, which makes them easy to miss and, unfortunately, the life stage most likely to transmit Lyme disease.
The blacklegged tick, often called the deer tick, is also expanding its range northward. Milder winters play a role, ticks can’t survive prolonged cold below about 14°F. Warmer winters with fewer extreme cold snaps let more ticks survive into spring, which can mean more questing nymphs once the weather turns.
Aptive's Pest Intelligence Center™ Summer Outlook predicts summer tick activity will rise more than 60% in several cities, including Dover, Boise, South Bend, Manchester, and Indianapolis, with the Mid-Atlantic the hottest region this year. Check daily and weekly local pest trends at the Pest Intelligence Center, or see the full 2026 Summer Pest Report for more detail.
“Starting around October and running through next June, adult female ticks will be actively seeking hosts,” said Rockwell. “Nymphs wake in March and April, and begin seeking their second host until around July. This April-July period is when nymphs are most likely to be encountered by humans across much of their range, and their small size and ability to carry Lyme and other transmittable diseases makes them especially dangerous.”
For homeowners, the practical takeaway is timing. The months when you’re most likely to be outdoors often overlap with the months when tiny nymphs are most active. That overlap, more than any single factor, explains why summer tends to bring the highest encounters and tick bites.
What does a tick bite look like?
A tick bite often looks like a small, itchy bump, and many bites go unnoticed entirely. That is part of what makes ticks tricky, you may never feel the bite that matters.
What does a Lyme disease rash look like?
A Lyme disease rash, known as erythema migrans,. typically appears 3 to 30 days after a bite and often expands outward in a bull's-eye pattern – a red ring around a lighter center. This rash shows up in more than 70% of people who develop Lyme, though not everyone gets one.
Other early Lyme disease symptoms can include fever, fatigue, and headache. Since these signs can be easy to brush off, it helps to stay alert after time outdoors. If a rash or these symptoms appear following a bite or time in tick habitat, contact a healthcare provider.
The content in this article is for informational purposes only and isn't intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about any symptoms or medical condition. Don't delay seeking emergency care for signs of a severe allergic reaction, such as difficulty breathing or swelling of the face or throat. Individual reactions to tick bites and Lyme disease vary, and no guarantees are made regarding the effectiveness of any prevention method described here. Aptive Environmental LLC provides pest control services only and doesn't offer medical advice. The company isn't liable for any damages or injuries resulting from the use of this information.
How to protect yourself from ticks
Good tick bite prevention comes down to a few consistent habits, and together they make a real difference. Knowing how to prevent Lyme disease starts with keeping ticks off your body and out of your yard.
To protect yourself outdoors:
- Use repellent: Apply an EPA-registered tick repellent and treat clothing and gear before heading into grassy, brushy, or wooded areas.
- Wear protective clothing: Wear long sleeves, tuck pants into socks, and choose light colors so ticks are easier to spot.
- Check after outings: Do a full tick check whenever you come indoors, including your scalp, waistline, and behind the knees.
- Stick to the center: Walk on cleared trails and avoid tall grass and leaf litter where ticks wait.
If you find an attached tick, knowing how to remove a tick safely matters. Use fine-tipped tweezers, grasp it close to the skin, and pull steadily upward without twisting.
How to protect your yard from ticks
To make your yard less inviting:
- Mow regularly: Keep grass short and trim bushes to reduce shady, humid tick habitat.
- Clear the edges: Rake leaf litter and clear brush, especially along fences and wooded borders.
DIY yard steps help, but they typically only last a season and can miss the high-risk habitat ticks favor. Aptive's proactive, data-informed approach targets tick habitat across your whole property, which makes it a more reliable option than yard work alone.
How to protect your pets from ticks
Pets spend more time in tall grass than we do, so ticks on pets are common. A few steps lower their risk and yours, since pets can carry ticks indoors.
- Use vet-recommended products: Give dogs a tick preventive recommended by your veterinarian.
- Don’t share dog products with cats: Never apply dog tick products to cats without veterinary guidance. Cats react very differently to certain ingredients.
- Check pets daily: Run your hands over your pet after outdoor time, focusing on ears, toes, and under the collar.
- Steer clear of tick habitat: Keep pets on cleared trails and away from tall grass, marshes, and wooded areas.
- Maintain the yard: A mowed, trimmed yard reduces tick habitat for pets too.
Talk with your veterinarian about the right plan for your specific animals, since the best option depends on species, age, and where you live.
When to contact a professional for tick control
The effectiveness of DIY tick treatment for yards depends on getting the timing, coverage, and product right, and treatments typically need reapplying every 6 to 8 weeks to stay effective. A professional service is built around keeping a schedule and coverage consistent, which is easy to fall behind on with a one-off DIY spray.
An Aptive professional treats accessible tick habitats across your property, and our Pest Intelligence Center helps us time each visit to local conditions. That proactive coverage helps reduce tick pressure and the risk of Lyme disease season after season.
FAQs about Lyme disease
Q: Which states are most at risk for Lyme disease?
New York, Pennsylvania, and New Jersey report the highest number of Lyme disease cases and together account for close to half of the U.S. total. Broader hotspots include the rest of the Northeast, the mid-Atlantic, and the upper Midwest, with smaller pockets of risk in California, Oregon, and Washington.
Q: When are ticks most active?
Ticks are most active from late spring through midsummer, roughly May through July, when nymphs are questing. Although this is peak tick season, the full season typically runs from April through September. Warm-weather months bring the highest number of encounters, though adult ticks can stay active into fall whenever temperatures are mild.
Q: What does a Lyme disease rash look like?
The Lyme rash typically shows up 3 to 30 days after a tick bite. It often starts small and expands outward over several days, and in many cases forms the classic bull's-eye pattern: a red ring around a lighter center, though it doesn't always look that textbook. It can be warm but is usually not itchy or painful. It shows up in more than 70% of people who develop Lyme, though not everyone gets a rash.
Q: How can I protect my pets from ticks?
Give dogs a vet-recommended tick preventive, and never use dog products on cats without veterinary guidance. Check pets daily after outdoor time, keep them out of tall grass, and maintain a mowed yard. Ask your veterinarian for a plan suited to your pet's species, age, and location.
