Tick Season in Pennsylvania: What to Know and How to Stay Safe

Pennsylvania has one of the most active tick populations in the entire country — and if you spend any time outdoors here, that’s something worth taking seriously. Pennsylvania consistently reports the highest number of total Lyme disease cases in the country, accounting for about 30% of all recorded cases nationally. That’s a striking figure, but it doesn’t mean you need to stay indoors all season.

Understanding when ticks are most active, which species live in your area, and what steps you can take to protect yourself and your family makes a real difference. This guide walks you through everything you need to know about tick season in Pennsylvania — from the first warm days of spring through the colder months when many people assume the risk has passed.

Key Insight: Ticks in Pennsylvania are not just a summer problem. Some species remain active well into late fall and even winter on warmer days, making year-round awareness essential.

When Is Tick Season in Pennsylvania

Many people think of tick season as a summer concern, but in Pennsylvania, the risk window is much wider than that. “Tick season” in Pennsylvania generally lasts from April to October, peaking during the spring and fall months. However, that timeframe doesn’t tell the whole story.

Tick activity is at its peak from spring into May and again from mid-August to November, but as long as the ground is dry and free of ice and the temperature is above 45 degrees, most tick species can be active. This means that even a mild January or February day can put you at risk if you’re walking through leaf litter or wooded areas.

While most Lyme disease cases are confirmed in the summer, October and November are when the number of adult ticks carrying Lyme disease is highest and they are most active, according to the state Department of Environmental Protection. Fall hikers and hunters are often caught off guard by this surge in adult tick activity.

Understanding the tick life cycle helps explain these patterns. Tick eggs emerge as larvae in late summer for their first feeding. Larvae then molt into nymphs, many becoming dormant until the next spring. Nymphs then molt into adult ticks, and this transition peaks in October through November. To learn more about how ticks reproduce and why populations can surge from year to year, see our guide on how ticks reproduce.

Pro Tip: Don’t let a cool fall day lull you into skipping a tick check. Adult blacklegged ticks are especially active in October and November — and they’re the primary carriers of Lyme disease in Pennsylvania.

Shifts in seasonal activity, likely due to climate change, are causing ticks to become active earlier in the year. Experts suggest climate change may play a role, as ticks thrive in warm and humid conditions that are becoming more common. The practical takeaway: the window of risk is expanding, and it pays to be prepared starting in early spring.

Types of Ticks Found in Pennsylvania

There are more than 900 species of ticks worldwide, at least 25 of which occur in Pennsylvania. While that number sounds overwhelming, a handful of species account for the vast majority of human encounters and health risks in the state.

Of these, two species account for more than 90 percent of identification requests submitted to Penn State: the blacklegged tick (Ixodes scapularis) and the American dog tick (Dermacentor variabilis). Three additional species are also worth knowing: the lone star tick, the Asian longhorn tick, and the winter tick.

Blacklegged Tick (Deer Tick)

The blacklegged tick has been expanding its presence in Pennsylvania and can now be found in nearly every county. It measures only one-eighth of an inch as an adult, and a nymph can be as small as a pinhead. That tiny size makes it easy to miss during a body check.

Adult ticks are present in the fall, throughout the winter, and in early spring. In the summer, when more people are outdoors wearing less clothing, they are often bitten by blacklegged nymphs — young ticks about the size of a poppy seed. The blacklegged tick is the species of greatest concern in Pennsylvania because of the diseases it carries.

American Dog Tick

The American dog tick is the most commonly encountered tick in Pennsylvania, appearing in most of the state’s counties. It’s only 3/16 of an inch as an adult, but after feeding, it can become engorged to the size of a grape.

American dog ticks prefer open locations with little or no tree cover, such as grassy fields and scrublands. Larvae are most common during the spring and fall, while nymphs and adults are found throughout the summer. Unfed individuals of all life stages can survive for more than a year between hosts, which makes them a persistent threat in your yard and surrounding areas.

Lone Star Tick

In Pennsylvania, the lone star tick is most common in urban areas of the southern half of the state. The reddish-brown tick has a white, star-shaped dot in the center of its abdomen and can grow to around a quarter of an inch in length. One of the more aggressive ticks, it pursues its host rather than waiting for hosts to come to it.

Larval lone star ticks are active during the late summer and fall, while nymphs and adults are active during the spring and summer. Previously a southern species, the lone star tick has been moving northward in recent years.

Asian Longhorned Tick

The Asian longhorned tick is invasive to Pennsylvania and has been recovered from the central and eastern counties. In its native range in Asia, this species prefers cattle as hosts. Unlike native ticks, this tick is parthenogenic — meaning females can reproduce without a male — and all life stages may be found on large animals. Its ability to reproduce rapidly makes it a species worth monitoring closely.

Important Note: If you find an unusual tick you don’t recognize, Pennsylvania’s Tick Research Lab at East Stroudsburg University can help identify it and test it for pathogens. Visit TickLab.org to learn more about submitting a tick for testing.

Tick-Borne Diseases in Pennsylvania

Ticks in Pennsylvania carry a range of diseases, and knowing what to watch for can help you seek treatment quickly if you’ve been bitten. Many species of ticks can transmit pathogens between animals and to humans. The most important of these in Pennsylvania are the bacteria that cause Lyme disease and Rocky Mountain spotted fever.

Lyme Disease

All 67 counties in the state have both the blacklegged tick — the primary vector for Lyme disease — and documented cases of Lyme. Depending on where you look in the state, 20–60% of blacklegged ticks are Lyme positive.

Lyme disease is highly treatable with antibiotics like doxycycline if caught early. The early hallmark signs of Lyme disease are fever, fatigue, head and joint aches, and a rash. If untreated, Lyme disease carried by blacklegged ticks can cause severe symptoms that affect the heart, nervous system, and joints.

Blacklegged ticks typically need to feed for 24 hours before Borrelia burgdorferi, the causative agent of Lyme disease, is transmitted. This is why prompt tick removal is so important — the sooner you find and remove a tick, the lower your risk.

Anaplasmosis

Blacklegged ticks are also known to vector Anaplasma spp. and Babesia spp., which can cause anaplasmosis and babesiosis, respectively. In 2023, Pennsylvania reported 1,292 anaplasmosis cases — a number that reflects both a growing tick population and an expanding geographic range of the blacklegged tick.

People with anaplasmosis will often have fever, headache, chills, and muscle aches. The course of treatment for most tick-borne diseases, including Lyme disease and anaplasmosis, is the antibiotic doxycycline, usually administered for 10 days.

Babesiosis

Babesiosis is caused by microscopic parasites that infect red blood cells and are spread by the blacklegged tick in Pennsylvania. Babesia infection can range from asymptomatic to life-threatening. Most infections cause fever, chills, sweats, and fatigue, and effective treatment is available for those who develop symptoms.

This malaria-like illness targets red blood cells, causing anemia and flu-like symptoms, and is especially dangerous for the elderly or immunocompromised. In 2023, 224 babesiosis cases were reported in the state. For more on tick-borne encephalitis and other serious viral tick diseases, see our overview of tick-borne encephalitis.

Rocky Mountain Spotted Fever

American dog ticks are the main vector of the pathogens that cause Rocky Mountain spotted fever in Pennsylvania, which is less common than Lyme disease but a potentially more serious illness. They have also been known to transmit tularemia and to cause canine tick paralysis.

Rocky Mountain Spotted Fever (RMSF) can be rapidly fatal if not treated within the first 5 days after symptoms occur. Symptoms include high fever, severe headache, and a characteristic spotted rash. If you suspect RMSF after a tick bite, seek medical attention immediately.

Powassan Virus

Powassan virus can be transmitted in as little as 15 minutes — making it one of the most alarming tick-borne threats in Pennsylvania. The virus is related to West Nile virus and is clinically similar, as patients present with fever, headache, vomiting, and signs of neurological impairment. The incubation period ranges from 1 week to 1 month, and there is no specific treatment aside from supportive care. Patients can develop encephalitis and meningitis, with approximately 10% of encephalitis cases resulting in death.

Common Mistake: Many people assume that if a tick was attached for less than a day, they’re completely safe from all tick-borne diseases. While this is generally true for Lyme disease, Powassan virus can be transmitted in as little as 15 minutes of attachment.

High-Risk Areas and Habitats in Pennsylvania

Knowing where ticks are most likely to be found helps you take targeted precautions rather than avoiding the outdoors altogether. In general, ticks tend to be found in wooded areas, tall grass or brush, the edges where woods and lawn meet, in the leaf litter, under ground-cover plants, and around stone walls and woodpiles where small mammals live.

There are a great deal of ticks present in Pennsylvania, particularly in more rural and suburban areas such as Happy Valley and Bucks County. But ticks are not limited to rural settings. Pennsylvanians may be at risk in places they weren’t before, like city parks or suburban gardens.

In Pennsylvania, western counties like Jefferson, Clarion, Elk, Clearfield, and Cameron experience especially high rates of Lyme disease. But relative to the rest of the country, Lyme disease risk is high across the state. About 51% of the blacklegged ticks in Southwestern Pennsylvania carry Lyme disease, according to the DEP.

Specific environments that warrant extra caution include:

• Forest edges and trail margins — where sunlight meets shade and humidity is consistent
• Tall grass and overgrown fields — especially in state parks, game lands, and rural properties
• Leaf litter and brush piles — common tick resting spots during cooler months
• Stone walls and woodpiles — shelters for small mammals that ticks feed on
• Suburban backyards — particularly those that border wooded areas or have wildlife activity

Ticks sense vibration and heat, so they usually like to hang out in tall grass or leaves. Once they feel that vibration from an animal or person coming through, they’ll climb on and attach. Walking in the center of trails and avoiding brushing against vegetation on the sides reduces your contact with questing ticks significantly. You might also be interested to learn about animals that eat ticks and how natural predators play a role in keeping tick populations in check.

How to Protect Yourself, Children and Pets During Tick Season in Pennsylvania

Protection starts before you head outside. A layered approach — combining clothing choices, repellents, and post-outing checks — gives you the best defense against tick bites during Pennsylvania’s long tick season.

Clothing and Physical Barriers

• Wear long-sleeved shirts, closed-toe shoes, and long pants as much as possible when outdoors to help prevent exposure to ticks.
• Tuck your long-sleeved shirts into your pants, and tuck your pants into your socks.
• Wear light-colored clothing to make ticks easier to identify.
• Walk in the center of trails and avoid brushing against tall grass or shrubs along the edges.

Repellents and Treated Gear

• Treat clothing and gear with products containing 0.5% permethrin. Permethrin can be used to treat boots, clothing, and camping gear and remains protective through several washings. Alternatively, you can buy permethrin-treated clothing and gear.
• Use EPA-registered insect repellents containing DEET, picaridin, IR3535, Oil of Lemon Eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone.
• Do not use insect repellent on babies younger than 2 months old. Do not use products containing OLE or PMD on children under 3 years old.

After Time Outdoors

• Perform a full-body tick check as soon as you come indoors, paying close attention to the scalp, behind the ears, underarms, groin, and behind the knees.
• Outdoor clothing can be tossed in a dryer to kill any ticks. Clothes can also be treated with the chemical permethrin to guard against ticks.
• Shower within two hours of coming indoors, which helps wash off unattached ticks.

Protecting Children

Children are often at higher risk simply because they spend more time playing in grass, leaves, and wooded areas. Apply repellent to children’s clothing rather than directly to skin when possible, and always check children thoroughly after outdoor play — including the hairline and ears, where ticks commonly hide.

Protecting Pets

During tick season — generally spring through fall in Pennsylvania — it is important to check your dog for ticks after being outside or at least once a day, since the pathogen that causes Lyme disease can be transmitted from the tick to your dog in as little as one day. Especially in long-coated dogs, checking for ticks is best done with both your eyes and your hands. Often, ticks buried deep in the fur can be felt even if they cannot be seen.

There are vaccines available for Lyme disease in pets. These vaccines can prevent or at least reduce the severity of Lyme disease should your pet be exposed. They are an added layer of protection that your veterinarian may recommend based on your pet’s lifestyle. For a full breakdown of tick prevention strategies for dogs, visit our guide on preventing tick-borne diseases in your dog.

Pro Tip: Don’t forget that even pets that stay in the yard can bring ticks indoors. A tick that hitches a ride on your dog can detach and find a human host inside your home.

Yard and Property Management

• Mow your lawn regularly.
• Keep firewood piles and bird feeders away from your home.
• Create a barrier of wood chips or gravel between your lawn and any wooded areas to reduce tick migration.
• Remove leaf litter and brush piles from around your home’s foundation.

What to Do If You Find a Tick in Pennsylvania

Finding a tick on your body can be unsettling, but staying calm and acting quickly is the best approach. The most important thing is to remove the tick as soon as possible using the correct technique — improper removal can increase your risk of infection.

How to Remove a Tick Safely

1. Use fine-tipped tweezers. Grab the tick with tweezers as close to the skin as possible and pull upward without jerking or twisting.
2. Do not squeeze the body. Do not grab the tick’s body, as this may cause it to inject blood into the skin.
3. Avoid folk remedies. Do not try to remove a tick with Vaseline, nail polish, or a hot match. The safest way is to use tweezers to grasp the tick close to the skin and pull straight out. These other methods can irritate the tick and cause it to regurgitate pathogens into your body.
4. Clean the area. Once the tick has been removed, clean the area and wash your hands with rubbing alcohol or soap.
5. Save the tick. Place it in a sealed plastic bag or small container with a lid. This allows you to have it tested if symptoms develop.

What About the Mouthpart?

Ticks don’t have heads like insects. The part that stays embedded is the mouthpart. If a small piece remains after removal, your body will usually expel it naturally. Clean the area and monitor for signs of infection, but don’t panic if the mouthpart breaks off.

After Removal: What to Watch For

According to the CDC, a tick usually needs to be attached for more than 24 hours in order to transmit Lyme disease. This means it is important to remove a tick as soon as possible once it has been spotted.

If you know that you’ve had a blacklegged tick on you for 36 hours or longer, the Infectious Disease Society of America advises that you can see your doctor for a single dose of oral doxycycline to prevent Lyme disease. The medication would need to be taken within 72 hours of finding and removing the tick.

If a rash develops or you experience a fever, contact a healthcare professional. Especially in Pennsylvania, where all of these tick-borne diseases are frequently encountered, if you have a nonspecific fever during the summer and have frequent outdoor activity, you should see your doctor, even if you never saw a tick on you.

Important Note: You can send a removed tick to the Pennsylvania Tick Research Lab at East Stroudsburg University for pathogen testing. A positive test result may allow you to receive treatment before you experience symptoms.

Reporting Tick Bites and Tick-Borne Illness in Pennsylvania

Pennsylvania has several resources in place to help residents report tick encounters and get appropriate follow-up care. Using these systems not only helps you but also contributes to statewide surveillance efforts that track tick populations and disease trends.

The Pennsylvania Tick Research Lab

The Pennsylvania Tick Research Lab can analyze your tick, testing for tick-borne diseases such as Lyme disease, anaplasmosis, and Rocky Mountain spotted fever. You can order your test online and learn whether you’re at risk before symptoms appear.

No kit is needed for collecting and sending a tick specimen. Simply place your tick in a sealed plastic bag and mail it, along with your order receipt, to the laboratory. After you complete the order process, you’ll receive instructions for mailing your tick. Results are typically returned within three business days.

The Tick App and TickSpotter

You can report your tick experience to resources like The Tick App or the University of Rhode Island’s TickSpotter, to identify the tick species and learn more about tick safety. These citizen science platforms help researchers understand where ticks are being found and what species are most active in different regions.

Pennsylvania DEP Tick Surveillance Program

The DEP’s Tick Surveillance and Testing Program is responsible for conducting statewide active tick surveillance to determine the distribution, prevalence, and expansion of tick populations throughout the Commonwealth. In addition, the Vector Management Laboratory identifies, enumerates, and prepares ticks for pathogen testing. After the ticks are prepared, they are tested for pathogens that can impact human health.

The pathogen list includes: Borrelia burgdorferi (causative agent of Lyme disease), Anaplasma phagocytophilum (causative agent of anaplasmosis), Babesia microti (causative agent of babesiosis), Deer Tick Virus (Powassan Virus Lineage II), Borrelia miyamotoi (causative agent of Hard Tick Relapsing Fever), and Borrelia mayonii (causative agent of Lyme disease).

Reporting to Your Healthcare Provider

If you develop symptoms after a tick bite — including fever, rash, fatigue, muscle aches, or headache — contact your healthcare provider promptly. Physicians in Pennsylvania are required to report confirmed cases of Lyme disease, anaplasmosis, ehrlichiosis, and Rocky Mountain spotted fever to the state Department of Health. A statewide advisory issued by Pennsylvania Health Secretary Dr. Debra Bogen advised medical officials, doctors, and hospitals to maintain “heightened clinical suspicion for tick-borne diseases.”

Early reporting and treatment are your best tools for a full recovery. Tick-borne diseases are a growing concern, but knowledge is power. With a few simple precautions and greater awareness, Pennsylvanians can enjoy the outdoors while minimizing their risk.

Spending time outdoors in Pennsylvania — whether you’re hiking, gardening, hunting, or simply walking your dog — is one of the great pleasures of living in the Keystone State. Tick season doesn’t have to change that. With the right knowledge and a consistent routine of checking yourself, your children, and your pets, you can stay safe and enjoy everything Pennsylvania’s outdoors has to offer. If you enjoy outdoor activities in Pennsylvania, you may also want to check out our guide to dove hunting season in Pennsylvania for more tips on staying safe in the field.