Of the many different tick species found throughout the world, only a select few bite and transmit disease to humans. These maps provide general insight into the expected distribution these human-biting ticks in the contiguous United States. Populations of ticks may be found outside noted areas. Although there are more than 800 species of ticks found throughout the world, fewer than 60 are known to bite and transmit disease to humans. Here are some of the more common ticks and the geographic locations where you'll most likely encounter them.

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* Note that adult ticks are the easiest to identify and male and female ticks of the same species may look different. Nymphal and larval ticks are very small and may be difficult to identify. Cases are reported from the infected person’s county of residence, not necessarily the place where they were infected.

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BLACKLEGGED TICK 

Ixodes scapularis

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Where found: Widely distributed in the northeastern and upper midwestern United States.

Transmits: Lyme Disease, babesiosis, 

anaplasmosis, and Powassan disease.

Comments: The greatest risk of being bitten exists in the spring, summer, and fall. However, adults may be out searching for a host any time winter temperatures are above freezing. Stages most likely to bite humans are nymphs and adult females