The Lyme disease risk map in the United States shows where reported Lyme disease cases or the ticks that can carry Lyme bacteria have been found. These maps help people understand which areas have greater known activity, but they do not predict an individual person’s chance of infection. The Centers for Disease Control and Prevention (CDC) publishes separate maps for human cases, tick distribution, and germs detected in ticks.
There is more than one type of Lyme disease map, so the meaning of the colors, dots, and shaded areas depends on the map being viewed. Some maps show where people have been reported with Lyme disease, while others show where ticks live or where Lyme disease bacteria have been found in collected ticks.
What does the Lyme disease risk map show?
A Lyme disease risk map provides a geographic overview of reported cases or evidence of tick activity associated with the disease. It helps readers identify areas where Lyme disease is more commonly reported and where precautions against tick bites are especially important. The map is a guide to regional patterns rather than a live measurement of the risk at every individual location.
The CDC's Lyme Disease Case Maps page includes maps of reported cases from 2023, 2010, and 1995. Comparing these time points helps show how the geographic distribution of reported Lyme disease has changed over time. The page also explains that a reported case is placed in the person's county of residence when that information is available, which may differ from the county where the infection occurred.
Which parts of the United States have more Lyme disease?
Lyme disease is most commonly reported in the northeastern, mid-Atlantic, and upper Midwestern United States. Some cases also occur along the Pacific Coast, where western blacklegged ticks can transmit the bacteria responsible for Lyme disease.
According to the CDC's Lyme disease prevention guidance, these regions account for most reported cases. However, risk is not uniform across an entire state or region. Local tick populations and conditions can differ between neighboring counties, communities, and outdoor locations.
For this reason, looking at a state-level map may not provide enough detail for planning a visit to a particular park, campground, or rural property. A county-level map and information from the local health department can provide more useful context.
How are Lyme disease case maps different from tick maps?
Two maps may show different patterns because they measure different things. Understanding what each one represents helps prevent misleading conclusions.
Maps of reported human cases
Case maps display information about people whose Lyme disease cases were reported to public health authorities. They can help identify geographic patterns and compare reported cases across different years. However, these maps do not necessarily show the exact places where people were bitten by ticks, and the number of reported cases in an area does not measure the risk at every outdoor location.
Maps of ticks and Lyme disease bacteria
Tick distribution maps show where particular tick species have been recorded or are expected to occur. Other maps show counties where researchers have detected Lyme disease bacteria in collected ticks. The CDC's Tickborne Pathogen Surveillance page provides maps showing where Lyme disease bacteria have been identified in blacklegged and western blacklegged ticks through December 2025.
These maps provide evidence about the geographic presence of ticks or pathogens, but they do not directly measure how likely someone is to become infected during a particular outdoor activity. Disease transmission depends on more than the presence of a tick species alone.
How should you interpret the colors and markings?
Always read a map's legend, title, location labels, and data dates before drawing conclusions. A red area, a shaded county, or a dot may represent a different type of information depending on the map. For example, a dot on a case map may represent a reported human case, while a shaded area on a tick map may represent the recorded or estimated distribution of a tick species.
Some important details to check include:
- What is being measured? Determine whether the map represents human cases, tick populations, or pathogens found in ticks.
- What period does it cover? Check the year or date through which the data were collected. A map based on older records may not reflect more recent changes.
- What geographic area is shown? State-level maps can hide differences between counties and smaller local areas.
- What does an unmarked area mean? The absence of a marker or record does not necessarily mean that Lyme disease bacteria or the ticks that carry them are absent.
The CDC's Tick Surveillance Data Sets page explains that a county with no records may have had limited tick collection, testing, or reporting. Therefore, an unmarked county should not automatically be interpreted as a place where tick exposure is impossible.
Does the map tell you your personal risk of Lyme disease?
No. A map can help you understand regional patterns, but it cannot calculate your individual chance of infection. Your circumstances may differ from the patterns shown on a regional map. For example, your activities, the outdoor environments you visit, and whether you encounter an infected tick can affect your exposure.
The CDC's Where Ticks Live guidance explains that a tick species being present in an area does not automatically mean that it transmits a particular disease there. Tick abundance can also vary locally, including within the same general region.
Tick exposure is not limited to remote forests or hiking trails. People may encounter ticks in yards, gardens, neighborhood green spaces, and other outdoor settings. A map should therefore be used as one source of information, not as a reason to assume that an unshaded location has no risk.
How can you use a Lyme disease risk map before traveling outdoors?
Before visiting a national park, campground, wooded trail, or other outdoor area, check the map for the destination rather than relying only on your home state's risk pattern. Review available county-level tick information and local public health advice. If the area is known for Lyme disease, plan to prevent tick bites even if the map does not show a high concentration of reported cases at your exact destination.
The CDC recommends several practical ways to reduce exposure to ticks:
- Use an Environmental Protection Agency (EPA)-registered insect repellent according to its label instructions.
- Wear long sleeves and long pants when appropriate for the setting, and consider clothing or equipment treated with permethrin.
- Check your skin, clothing, equipment, and pets for ticks during and after outdoor activities.
- Shower soon after returning indoors to help remove unattached ticks.
- Remove an attached tick promptly rather than waiting for a healthcare appointment.
These precautions are useful because blacklegged ticks may be active during more than one season. The timing of outdoor activity and local conditions should be considered alongside the geographic information on the map.
What if you develop symptoms after possible tick exposure?
A map cannot confirm or rule out Lyme disease. If you develop a new or expanding rash, fever, unusual fatigue, headache, or muscle and joint aches after possible tick exposure, consider contacting a healthcare professional. These are examples of symptoms that can occur with Lyme disease, but they can also have other causes.
The CDC's information on Lyme disease signs and symptoms advises seeking medical attention when concerning symptoms occur after a tick bite or after living in or traveling to an area where Lyme disease occurs. Share your travel history, outdoor activities, and any known tick bites with the healthcare professional, since this information may help guide the evaluation.
Where can you find reliable Lyme disease maps?
The CDC is a useful starting point because it provides separate resources for reported human cases, tick distributions, and pathogens identified in ticks. Its maps and supporting data can be found on the following pages:
- CDC Lyme Disease Case Maps — compares reported human cases across selected years.
- CDC Tickborne Pathogen Surveillance — shows where selected pathogens have been identified in ticks.
- CDC Tick Surveillance Data Sets — provides information about tick and pathogen surveillance records by county.
- CDC Lyme Disease Prevention — offers guidance on reducing exposure to ticks and preventing Lyme disease.
For information about a specific destination, local or state health departments may provide additional regional guidance. Using these resources together can give a clearer picture of reported cases and known tick activity than relying on a single map alone.