Ticks in Wisconsin

Written by Phillip George · Last updated: July 24, 2026

Ticks in Wisconsin: what to actually watch for

Wisconsin sits at the heart of the Upper Midwest's tick belt, alongside Minnesota. Blacklegged ticks are widespread — heaviest in the wooded north and west — and the state is a hotspot not just for Lyme disease but for anaplasmosis, babesiosis, and Powassan. Wisconsin even gave its name to a tick-borne germ: a form of ehrlichiosis (Ehrlichia muris eauclairensis) first identified in the Eau Claire area. This guide covers the species, the geography, and what to do after a bite.

Key takeaways for Wisconsin

• An Upper-Midwest hotspot: blacklegged ticks are established across much of the state, with the highest densities in northern and western wooded counties.
• More than Lyme: anaplasmosis, babesiosis, and Powassan virus are all present, plus a regionally-discovered ehrlichiosis.
• Nymph season is the danger window: late spring through midsummer, when tiny nymphs are questing.

Which ticks you'll actually encounter

• Blacklegged / deer tick (Ixodes scapularis) — the key disease vector, carrying Lyme, anaplasmosis, babesiosis, Powassan, and the Eau Claire form of ehrlichiosis. Densest in northern and western forests.
• American dog tick (Dermacentor variabilis) — common in grasslands and prairies, especially central and southern Wisconsin; a nuisance biter.
• Lone star tick (Amblyomma americanum) — not established but occasionally found and worth watching as its range shifts north.

Source: Wisconsin DHS — Illnesses spread by ticks.

Where and when risk is highest

The northern and western thirds of Wisconsin — heavily forested counties and the driftless area — carry the highest blacklegged tick densities, though risk exists statewide. Ticks are active whenever it is above freezing; the blacklegged nymphs that cause most human cases peak from May through July. Wooded trails, leaf litter, and brushy edges are the highest-exposure spots.

Tick-borne diseases reported in Wisconsin

• Lyme disease — the most common; Wisconsin reports among the highest case counts in the Midwest.
• Anaplasmosis and babesiosis — increasing, from the same blacklegged tick.
• Powassan virus — rare but serious.
• Ehrlichiosis — including the Ehrlichia muris eauclairensis form first identified in Wisconsin.

For symptoms and timelines, see our tick-borne disease symptoms in humans guide.

Found a tick in Wisconsin? Do this

1. Remove it promptly with fine-tipped tweezers — follow our tick removal guide.
2. Identify it using our tick identification guide to tell a blacklegged tick from a dog tick.
3. Record the date and location and monitor for a rash or flu-like symptoms for several weeks.
4. Contact a healthcare provider if symptoms develop; Wisconsin clinicians are experienced with the full range of tick-borne illness.

Official Wisconsin resources

• Wisconsin DHS — Illnesses spread by ticks
• Wisconsin DHS — Lyme disease
• Wisconsin DHS — Lyme disease data
• CDC — What to do after a tick bite

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