Men, young children, and adults over 50 are the groups most likely to get Lyme disease. Geography matters even more than demographics: living in or visiting the northeastern, mid-Atlantic, or upper midwestern United States puts you at the highest risk. Roughly 476,000 people are diagnosed and treated for Lyme disease each year in the U.S., though only about 89,000 cases were formally reported to the CDC in 2023.
Age and Sex Patterns
Lyme disease hits two age groups hardest: children between 5 and 9 years old and adults between 50 and 79. The pattern makes sense when you consider behavior. Young kids play outside in grass, leaf litter, and wooded edges where ticks thrive. Adults in the 50-to-79 range tend to spend more time gardening, hiking, and doing yard work in tick habitat.
Men account for a slightly larger share of cases than women, roughly 56% versus 44%. This likely reflects differences in outdoor exposure rather than any biological susceptibility. Men in this age range are more likely to work or recreate in wooded areas without taking tick-prevention steps like wearing treated clothing or doing thorough tick checks.
Where You Live Matters Most
Two geographic hot spots account for the vast majority of U.S. cases. The first stretches across the Northeast and mid-Atlantic, from Maine down through Virginia, with a concentration in southern New England, New York, New Jersey, and eastern Pennsylvania. The second sits in the upper Midwest, centered on Wisconsin and Minnesota. Both regions have expanded significantly over the past two decades. The number of high-incidence counties in the Northeast grew more than 320% between 1993 and 2012, jumping from 43 counties to 182. The upper Midwest saw a roughly 250% increase over the same period.
The northeastern hot spot has also shifted over time, moving westward and northward away from the northern New Jersey coast into east-central Pennsylvania. In the upper Midwest, the center has stayed relatively stable in northwestern Wisconsin. If you live in or travel to these areas, your risk is substantially higher than someone in the Southeast or West Coast, where cases remain rare.
Outside the U.S., Lyme disease is common across central and eastern Europe, where about 14% of ticks carry the bacteria. Parts of northeastern Asia, particularly northeastern China, have even higher tick infection rates, averaging around 17.5%. The disease exists on every continent in the Northern Hemisphere with temperate forests.
High-Risk Occupations
People who work outdoors in wooded or brushy environments face the clearest occupational risk. Forest workers and farmers are about 2.4 times more likely to test positive for Lyme disease exposure compared to indoor workers. That elevated risk comes from daily, prolonged contact with tick habitat during the months when ticks are most active.
Other outdoor occupations you might expect to carry risk, like veterinary work, animal breeding, and military service, don’t show a statistically significant increase. The key factor isn’t just being outdoors but being in the specific habitat ticks prefer: deciduous forest with leaf litter and well-drained, sandy soils. Landscapers, utility workers, trail maintenance crews, and land surveyors in endemic areas fall into this higher-risk category even though fewer studies have focused on them directly.
The Habitat That Breeds Ticks
Blacklegged ticks, the species responsible for transmitting Lyme in the eastern U.S., thrive in a specific type of environment. They prefer deciduous forests with oak as a dominant tree species, growing on well-drained sandy or loamy soils over sedimentary rock. Leaf litter on the forest floor is critical because ticks overwinter in the top layer of soil and debris. They need that insulating blanket of leaves to survive cold months.
Ticks do poorly in conifer forests, waterlogged soils, and grasslands. Acidic, clay-heavy soils that retain moisture are hostile to them. So if your property backs up to a dry oak forest with a thick layer of fallen leaves, your yard is prime tick territory. If you’re surrounded by open meadow or dense pine, you’re in a much lower-risk setting. Stone walls, woodpiles, and the brushy transition zone between lawn and forest are particularly high-density areas for ticks on residential properties.
Seasonal Timing
Most Lyme disease infections happen between May and August, when the nymphal stage of the tick is most active. Nymphs are roughly the size of a poppy seed, making them far harder to spot than adult ticks. Peak nymphal activity hits in June and July. Adult ticks are active in spring and again in fall, but they’re larger and more likely to be noticed and removed before transmitting the bacteria, which typically requires the tick to be attached for 36 to 48 hours.
This seasonal pattern explains why summer is the danger zone. You’re more likely to be outside in shorts and short sleeves, spending time in tick habitat, and the smallest, hardest-to-detect ticks are at their most active.
Pet Owners and Yard Exposure
Owning a dog or cat that goes outdoors increases your chances of encountering ticks at home. Households with pets are about 1.8 times more likely to find ticks crawling on family members and 1.5 times more likely to find ticks attached to someone compared to pet-free households. Dogs and cats carry ticks from wooded areas and brush into your living space, where the ticks can transfer to people.
Interestingly, pet ownership alone doesn’t translate into higher rates of confirmed Lyme disease. The likely explanation is that people who find ticks on themselves more frequently also remove them more quickly, before the bacteria can be transmitted. Still, pets serve as a consistent pipeline for bringing ticks into close contact with you and your family, making tick checks after outdoor time more important in pet-owning households.
Putting the Risk Factors Together
Your overall risk is a combination of where you are, when you’re outside, what you’re doing, and how often you check for ticks afterward. A 7-year-old boy playing in the woods behind his house in Connecticut in June sits near the top of the risk spectrum. A retired couple doing regular yard work at a wooded property in Wisconsin is close behind. An office worker in Arizona with no pets faces almost no risk at all.
The factors that matter most, ranked roughly by impact: living in or visiting an endemic region, spending time in deciduous forest or its edges during May through August, working outdoors in wooded settings, being male, being in the 5-to-9 or 50-to-79 age ranges, and having pets that roam through brush or woods. None of these factors alone guarantees infection, but stacking several together is what pushes risk from theoretical to likely.