The State Parks With The Most Tick-Borne Illness

A single walk through tall grass can end with a blacklegged tick latched behind a knee, and in the country's Lyme disease strongholds that walk often happens inside a state park. The Northeast, the mid-Atlantic, and the upper Midwest carry the heaviest tick-borne disease burden in the United States, and the wooded parks in those regions put people directly into the habitat where deer, mice, and infected ticks overlap. The parks below have drawn documented tick activity, published research, or firsthand accounts of infection. They are ranked by the severity of the tick-borne disease problem in their surrounding region, starting with the states that report the most Lyme disease cases in the nation.

1. Pine Grove Furnace State Park, Pennsylvania

Pennsylvania reports more Lyme disease than any other state, and Pine Grove Furnace sits in the wooded ridge country where the risk runs highest. The park anchors the southern end of the Michaux State Forest and marks the halfway point of the Appalachian Trail, so through-hikers and day visitors move through the same tick habitat. Melissa Colucci, who owned a cabin at the park, was bitten there and spent two years being misdiagnosed with multiple sclerosis, fibromyalgia, and Parkinson's disease before a neurologist tested her for Lyme. By then the infection had gone untreated for years and required nine months of intravenous antibiotics. Her account is a reminder that a bite in these woods can go unnoticed until the symptoms mimic something else entirely.

2. Green Lakes State Park, New York

New York averages more than 17,500 new Lyme disease cases a year, and Green Lakes, near Fayetteville, is one of the parks where researchers have gone looking for the source. A lab team from SUNY Upstate Medical University has collected and tested adult deer ticks at the park using flagging, dragging, and dry-ice traps, confirming the presence of infected ticks along its trails. Multiple runners who train on the loop around the park's two glacial lakes have contracted Lyme disease. The wooded paths that make the park a draw for runners and hikers are the same corridors where ticks wait on the vegetation.

3. Harriman State Park, New York

Harriman is the second-largest park in New York's system, with more than 200 miles of trails winding through 46,000 acres of dense forest in Rockland and Orange counties. Its large deer population and heavy foot traffic combine to give it a high tick count, and it lies in the Lower Hudson Valley, one of the regions where New York State surveys have detected the pathogens for Lyme disease, anaplasmosis, babesiosis, and Powassan virus in blacklegged ticks. The park's popularity with hikers from the New York City area means a large number of people pass through prime tick habitat every warm-weather weekend.

4. Round Valley Reservoir, New Jersey

New Jersey ranks among the top states for Lyme disease, close behind Pennsylvania and New York, and Round Valley's heavily wooded trails run through a well-known tick population in the Hunterdon County hills. The reservoir draws hikers, anglers, and backcountry campers to shoreline paths that pass through exactly the leaf-litter and brush ticks favor. Mike Gallagher, a musician who worked for decades in New Jersey's state parks, absorbed several tick bites over the course of his career before a 2025 Lyme diagnosis. The infection attacked his nervous system, cost him hearing and short-term memory, and took the use of his arms and shoulders, leaving him unable to hold a guitar. His case shows that even people who know the outdoors well can be caught off guard.

5. Devil's Lake State Park, Wisconsin

Devil's Lake is Wisconsin's most-visited state park, drawing well over 2 million people a year to its 500-foot quartzite bluffs and the network of nearly 30 miles of trails around the lake. Wisconsin records more than 3,000 Lyme disease cases annually, and the number reported statewide has tripled over the past 15 years. The state's health department notes that ticks are now found in all 72 counties, and the mix of wooded trail and open bluffland at Devil's Lake creates the edge habitat where ticks concentrate. Its sheer visitor volume puts more people in contact with that habitat than almost any other park in the state.

6. Jay Cooke State Park, Minnesota

Minnesota ranks among the top states for Lyme disease, with more than 2,000 cases reported in a recent year, and Jay Cooke has been a focus of research on ticks and the illnesses they carry. The park protects the lower reaches of the St. Louis River about 15 miles southwest of Duluth, and its heavily wooded trails along the river gorge run through prime deer-tick territory. Minnesota also logged 627 anaplasmosis cases and a record 89 babesiosis cases in 2024, both diseases carried by the same blacklegged tick responsible for Lyme, and both concentrated in the state's forested north where Jay Cooke sits.

7. Itasca State Park, Minnesota

Itasca is Minnesota's oldest state park and the place where visitors wade across the infant Mississippi River at its headwaters. It draws large crowds each year to a landscape of old-growth pine, more than 100 lakes, and forested trails, and that diverse terrain makes it a high-exposure area for ticks. Lyme disease in Minnesota has climbed sharply, from fewer than 300 annual cases two decades ago to well over a thousand in recent years, driven by warmer winters and growing deer and mouse populations. The park's popularity means a steady stream of families walking the same wooded paths where ticks are active from spring through fall.

8. Starved Rock State Park, Illinois

Illinois has seen a steep rise in tick-borne illness over the past decade, and Starved Rock, the state's most-visited park, puts more than 2 million people a year into its wooded canyons and river trails. The blacklegged tick, the primary Lyme carrier in Illinois, thrives in the park's forested terrain, which supports a large deer population. In April, Stacy Riley, her family, and their dog picked up an estimated 30 to 35 ticks during a short walk at nearby Rock Cut State Park, a reminder of how quickly an encounter can escalate in northern Illinois parkland. Starved Rock's combination of dense woods and heavy visitation places it among the state's higher-risk sites.

9. Mississippi Palisades State Park, Illinois

Mississippi Palisades runs along the bluffs above the Mississippi River in northwestern Illinois, a stretch of forested ridge trails that sit squarely in blacklegged tick country. The Illinois Department of Public Health recorded more than 1,000 tick-borne disease cases in a recent year, and the wooded bluff trails here carry the same risk that has driven up emergency-room visits for tick bites across the state. The park's shaded ravines and river-edge forest hold moisture and leaf litter well, the conditions ticks depend on to survive between hosts.

10. Ridley Creek State Park, Pennsylvania

Ridley Creek sits just outside Philadelphia and has been a study site for research on Lyme disease prevalence in state parks, which places it on the map for anyone tracking where infected ticks turn up. Pennsylvania's status as the nation's Lyme leader is driven partly by these suburban-edge parks, where dense deer populations live close to large numbers of people. The park's wooded trails and creek valley provide the humid, sheltered ground blacklegged ticks need, and its location near a major metro area means heavy year-round use of that habitat.

Reducing Your Risk On The Trail

The state health and natural-resource agencies across these regions recommend the same layered approach to prevention. Apply an EPA-registered repellent containing 20 to 30 percent DEET to exposed skin and clothing, and wear long sleeves and long pants with the cuffs pulled down over your socks to block ticks from reaching skin. Staying on cleared trails and avoiding tall grass and dense brush keeps you out of the vegetation where ticks wait for a host. Check your body thoroughly during and after a hike, shower within two hours of coming indoors, and run worn clothing through a dryer on high heat for 10 minutes to kill any tick that hitched a ride. Tick-borne illnesses respond well to treatment when caught early, so a rash or fever in the days and weeks after a park visit is worth a prompt call to a doctor. The parks on this list are not places to avoid; they are places to enter prepared.

This article discusses a health topic that some readers may find distressing. Anyone concerned about a possible tick bite or symptoms of a tick-borne illness should consult a licensed medical professional.