Ticks are tiny arachnids that feed on the blood of mammals, birds, and reptiles. They are known to spread various diseases through their bites, such as Lyme disease, Rocky Mountain spotted fever, tularemia, babesiosis, and ehrlichiosis. Ticks thrive in areas with dense vegetation and high humidity, especially forests, grasslands, and brushy areas. But which U.S. state has the highest populations and risk of tick bites? Let’s take a closer look at the states with the most ticks.
Northeastern and Mid-Atlantic States
Many of the top states with the most ticks are found in the northeastern and mid-Atlantic regions of the United States. These areas provide ideal habitats for ticks, with their temperate climates, heavy forestation, and high rainfall. Ticks are especially abundant in these states during the spring and summer months.
Maine
Maine ranks among the top states in the U.S. for cases of Lyme disease, spread by blacklegged ticks or deer ticks. The deer tick population has been increasing in Maine since the late 1980s. A 2021 report found that cases of Lyme disease have tripled in Maine over the last decade. The rising temperatures due to climate change allow ticks to start being active earlier in the spring and extend their activity into the fall.
Vermont
Vermont has one of the highest rates of Lyme disease infection in the country. The blacklegged tick is widespread across the state, especially in wooded and grassy habitats. The tick season in Vermont runs from early spring through late fall, peaking in June and July. Increased awareness and testing may play a role in Vermont’s high reported Lyme disease rates.
New Hampshire
New Hampshire has a high risk of Lyme disease, with an estimated 1,373 cases per 100,000 residents. The majority of cases occur in the southeastern part of the state. New Hampshire also has populations of the Lone Star tick, which can transmit ehrlichiosis, tularemia, and the red meat allergy alpha-gal syndrome.
Connecticut
Connecticut has one of the highest rates of Lyme disease in the U.S., largely due to its suitable tick habitat including forests and suburban areas. Deer ticks infected with Lyme bacteria are found statewide. The infection rate in ticks may exceed 50% in some parts of the state. Connecticut also has American dog ticks, Lone Star ticks, and other species.
New Jersey
New Jersey has a high risk of tick-borne diseases, especially Lyme disease which is transmitted by the blacklegged tick. A 2019 study estimated over 2800 confirmed Lyme disease cases annually in the state. American dog ticks, Lone Star ticks, and brown dog ticks are also present in New Jersey.
New York
Upstate New York is a national hot spot for Lyme disease, with high infection rates found in deer ticks. The Lower Hudson Valley region also has abundant deer tick populations. Lone Star ticks have spread northward in the state in recent years and can transmit other diseases. Overall, New York reports over 3000 cases of Lyme annually.
Delaware
Delaware has rapidly rising Lyme disease case numbers, with over 400 confirmed cases per year recently. The highest risk areas are in the northern part of the state. Both deer ticks and Lone Star ticks are found in Delaware and can transmit various diseases.
Maryland
Maryland has populations of deer ticks carrying Lyme disease, as well as Lone Star ticks and American dog ticks. Lyme is widespread but more common in the northern and central counties of the state. Tick season peaks from April through September. Over 2000 confirmed Lyme cases occur annually.
Midwestern States
While the northeast U.S. is most associated with Lyme disease, the upper Midwestern states also rank high for cases. Changing tick habitats and increased surveillance may contribute to higher numbers being reported in these areas.
Wisconsin
Wisconsin has some of the highest Lyme disease rates in the country, with over 1,800 confirmed cases per 100,000 residents. Deer ticks infected with Lyme bacteria are widespread across the state, except for some northern counties. Lone Star ticks have also expanded their range within Wisconsin.
Minnesota
Minnesota has a high incidence of Lyme disease, with the highest risk areas in the north-central and southeastern parts of the state. Deer ticks infected with Lyme bacteria are present in wooded habitats. American dog ticks, Lone Star ticks, and brown dog ticks are also found in the state.
Illinois
Illinois is a high-incidence state for Lyme disease, with over 230 confirmed cases annually, primarily in the northern part of the state. Deer ticks and Lone Star ticks are both potential vectors. The range of the Lone Star tick has increased in the southern area of Illinois.
Indiana
Most tick-borne illnesses in Indiana are associated with the American dog tick, but deer ticks have become established in some areas. The highest risk of Lyme disease is in the northwest region, while ehrlichiosis is more common in central and southern counties. Indiana sees over 100 cases of Lyme annually.
Ohio
Ohio has growing populations of deer ticks that can transmit Lyme disease, mostly in wooded areas and tall grasses. Over 300 Lyme cases are reported annually in the state. Lone Star ticks are also emerging and carry diseases like ehrlichiosis and Rocky Mountain spotted fever.
Southern States
While more associated with other tick species, some southern states still have moderate rates of Lyme disease as deer tick populations expand. The warm, humid climate allows for longer tick seasons.
Virginia
Virginia has rising rates of Lyme disease in the western part of the state as deer ticks spread. The highest risk areas include Shenandoah National Park. Lone Star ticks are very common statewide and can cause ehrlichiosis and Southern tick-associated rash illness (STARI).
West Virginia
Deer ticks and Lyme disease are becoming more prevalent in West Virginia, especially in the eastern panhandle and northeastern region. The state sees over 100 confirmed Lyme cases per year. Lone Star ticks are abundant and transmit diseases like ehrlichiosis and Rocky Mountain spotted fever.
North Carolina
North Carolina has populations of deer ticks capable of transmitting Lyme disease, most notably along the coast and in the mountains. The piedmont region has also seen growth in numbers. Lone Star ticks are the most common species statewide.
Arkansas
Arkansas has rising cases of tick-borne diseases like Lyme disease and ehrlichiosis. Most cases are attributed to Lone Star ticks, followed by American dog ticks. Deer tick numbers are increasing, especially in the Ozark Mountains region in the northwest part of the state.
South Carolina
South Carolina has a mixture of tick species including Lone Star ticks, American dog ticks, deer ticks, and others. Lyme disease cases are increasing as deer ticks spread to new areas. The highest Lyme risk areas are along the coast and in the northwestern part of the state.
Western States
The West Coast states generally have lower tick populations and Lyme disease rates. But certain areas still pose moderate tick risks, especially forests with high humidity.
Oregon
Oregon has populations of deer ticks capable of transmitting Lyme disease, mostly concentrated along the northern coast and in the western region of the state. The highest incidence is seen in Curry County. Overall tick numbers are expanding in western Oregon’s moist habitats.
Northern California
In California, deer ticks carrying Lyme bacteria are primarily found in the northern coastal counties as well as the Sierra Nevada region. Cases have increased rapidly in recent years. American dog ticks, Pacific Coast ticks, and Western black-legged ticks also inhabit the state.
Washington
Washington state has pockets of deer ticks that can spread Lyme disease, mostly on the western side of the Cascade Mountains. Five counties account for over 90% of reported cases, led by Okanogan, Ferry, and Whatcom counties. Tick populations appear to be growing in western Washington.
Conclusions
Based on the available data, the northeastern and mid-Atlantic states have the highest risk and totals of confirmed Lyme disease cases. The top states include Maine, Vermont, New Hampshire, Connecticut, New Jersey, New York, and Maryland. However, the upper Midwest including Wisconsin and Minnesota also rank high, along with several southern states like North Carolina, Virginia, and Arkansas.
Some key takeaways:
- Deer ticks (or blacklegged ticks) spread most Lyme disease in the U.S. and thrive in forests and grassy areas.
- Lone Star ticks are also abundant in many states and transmit other diseases.
- Warmer weather and changing habitats contribute to tick expansion.
- Increased surveillance and testing may account for more cases being reported.
- No state is completely tick-free, but risks vary by exact location.
To prevent tick bites and tick-borne disease, use repellent, wear protective clothing, check your body for ticks after being outdoors, and consider treating clothing and gear with permethrin. Prompt tick removal and awareness of symptoms can help reduce transmission risk. Consult your healthcare provider if you suspect a tick-related illness.