New Hampshire is home to several tick species, and their populations have been expanding steadily across all ten counties. The blacklegged tick, which transmits Lyme disease and several other infections, is now the state’s biggest public health concern. Whether you’re hiking the White Mountains, gardening in the Seacoast region, or letting your dog out in the backyard, understanding which ticks are out there and how to deal with them makes a real difference.
Tick Species Found in New Hampshire
The American dog tick is the most frequently encountered tick in the state. It’s about 1/8 inch long, brown and tan, with a mottled pattern on its back that makes it relatively easy to identify. This species has spread to every county in New Hampshire and completes its life cycle over two years, feeding on three separate hosts along the way. American dog ticks can transmit Rocky Mountain spotted fever, though this is uncommon in the Northeast.
The blacklegged tick is the second most common species, and its numbers are climbing fast enough that it may soon take the top spot. Formerly called the deer tick (the two were considered separate species until 1993), it’s smaller and more rounded than the American dog tick and lacks the mottled markings. This is the tick that carries Lyme disease, and it’s the one New Hampshire residents should pay the most attention to.
A few other species round out the picture. The winter tick looks similar to the American dog tick but is active in colder months and spends its entire life on a single host, typically moose. Severe winter tick infestations have been a major factor in New Hampshire’s moose decline. The brown dog tick is uncommon but probably present statewide. It’s slightly smaller and reddish-brown without mottling, and it primarily targets dogs. The lone star tick, an aggressive biter common in the southeastern U.S., is only rarely encountered in New Hampshire for now.
When Ticks Are Most Active
Blacklegged tick nymphs are most active from May through August. This is the window when most people pick up tick-borne infections, partly because nymphs are tiny (roughly the size of a poppy seed) and easy to miss on your skin. Adults become active in fall and can remain active through winter on days when temperatures climb above freezing, meaning there’s no truly tick-free season in New Hampshire.
American dog ticks follow a more predictable warm-weather schedule, peaking in spring and early summer. Winter ticks, as the name suggests, are active from fall through spring and primarily affect wildlife rather than people.
Diseases Ticks Carry in New Hampshire
The blacklegged tick is responsible for transmitting five different pathogens in the state: Lyme disease, anaplasmosis, babesiosis, Borrelia miyamotoi (a relapsing fever), and Powassan virus. Lyme disease is by far the most common of these, and New Hampshire consistently ranks among the highest-incidence states in the country.
Lyme disease typically starts with an expanding red rash at the bite site, often with a bull’s-eye pattern, along with fever, fatigue, and joint pain. Not everyone develops the rash, though, which is one reason infections sometimes go unrecognized. Anaplasmosis and babesiosis cause flu-like symptoms and can be serious in older adults or people with weakened immune systems. Powassan virus is rare but potentially severe, causing inflammation of the brain, and unlike other tick-borne diseases, it can be transmitted within minutes of a tick attaching.
How to Protect Yourself
Clothing treatment with permethrin is one of the most effective defenses. Permethrin is an insecticide that kills ticks on contact. You spray it on clothing, shoes, hats, backpacks, and gear (never directly on skin). Spray each side of the fabric for 30 to 45 seconds outdoors, let it dry completely before wearing, and it will last about six weeks or six washes. Professionally treated clothing lasts roughly twice as long. Permethrin is safe for people, including children over two months and pregnant women, but it is toxic to cats.
For exposed skin, DEET and picaridin are the most reliable repellents. Concentrations of 20% to 35% DEET work well for most outdoor activities. Higher concentrations don’t repel ticks any better, they just last longer, up to eight hours. Picaridin at 20% provides eight to 14 hours of protection against ticks. A compound called IR3535, found in some lotions and sprays, offers nine to 11 hours of protection depending on the formulation.
Oil of lemon eucalyptus is a registered repellent but is less effective against ticks and doesn’t last as long. It also hasn’t been tested in children under three and shouldn’t be used on them. Products that do not work against ticks include citronella, botanical oils (cinnamon, peppermint, geranium, soybean), vitamin supplements, herbal remedies, and repellent bracelets.
How to Remove a Tick
If you find an attached tick, use fine-tipped tweezers to grasp it as close to the skin as possible and pull straight up with steady, even pressure. Don’t twist, squeeze the body, or try to burn it off. Clean the bite area with rubbing alcohol or soap and water afterward.
Save the tick. Place it in a sealed plastic bag and store it in the freezer if you can’t mail it within 24 hours. New Hampshire residents can submit ticks to the University of New Hampshire’s testing lab for pathogen analysis. You order the test online, write your confirmation code on the bag, and either mail it to UNH’s lab in Durham or drop it off in person in a red cooler in the vestibule of Gregg Hall on the main campus. Results come back by email, often within three days of the lab receiving your sample. Each tick costs a separate testing fee, and if you submit multiple ticks in one order, the report will only tell you whether any of them tested positive, not which individual tick carried the pathogen.
Preventive Treatment After a Bite
A single dose of the antibiotic doxycycline can reduce the risk of developing Lyme disease after a tick bite, but current guidelines reserve this for high-risk bites. A bite qualifies as high-risk when all three of the following are true: the tick is identified as a blacklegged tick, the bite happened in an area where Lyme disease is common (all of New Hampshire qualifies), and the tick was attached for at least 36 hours.
Estimating attachment time can be tricky. A blacklegged tick that’s flat and small likely attached recently. One that’s visibly engorged, swollen and gray or greenish, has probably been feeding for a day or more. If you meet the high-risk criteria, the preventive dose needs to be taken within 72 hours of removing the tick to be effective. This applies to adults and children of all ages, though for young children and pregnant women, the decision involves weighing the risks more carefully with a clinician.
Getting a removed tick tested through UNH’s program can help inform these decisions, though results may take several days. If the timing is tight, don’t wait for test results before discussing prophylaxis with a provider.
Reducing Ticks Around Your Property
Ticks thrive in shady, moist environments with leaf litter and tall grass. Keeping your lawn mowed, clearing brush and leaves from the edges of your yard, and creating a three-foot barrier of wood chips or gravel between your lawn and wooded areas can reduce the number of ticks near your home. Stacking firewood in dry, sunny spots and removing stone walls or ground cover that attract rodents (the primary hosts for young blacklegged ticks) also helps.
Tick checks after spending time outdoors remain one of the simplest and most effective habits. Blacklegged nymphs are small enough to hide in skin folds, behind ears, along the hairline, and in the groin area. Showering within two hours of coming inside and running your clothes through a hot dryer for at least 10 minutes kills any ticks that hitched a ride.