
Deer tick
Ixodes scapularis
Established in Wisconsin
- Size:
- Small, a sesame seed (nymph: a poppy seed)
- Look for:
- Reddish-orange body, solid dark shield, black legs, no pattern
- Carries:
- Lyme, babesiosis, anaplasmosis, Powassan
The ticks you are most likely to find in Wisconsin, with photos and the size, color, and markings that tell them apart. Only the deer tick carries Lyme disease. Below the chart, see which types live in your county.

Ixodes scapularis
Established in Wisconsin

Dermacentor variabilis
Established in Wisconsin

Amblyomma americanum
Not established in Wisconsin

Rhipicephalus sanguineus
Found nationwide, the one tick that infests homes and kennels indoors

Amblyomma maculatum
A southern tick spreading north into the mid-Atlantic

Haemaphysalis longicornis
A newer arrival, established in the mid-Atlantic and spreading north
Wisconsin establishment is shown for the three ticks CDC tracks by county; the others carry a regional range note. Source: CDC tick surveillance (ArboNET Tick Module), 2025. County surveillance is coarse: “not established” is a lack of records, not proof a tick is absent.
These are the three ticks CDC maps county by county, not the only ticks in Wisconsin: the brown dog, Gulf Coast, and Asian longhorned ticks are in the chart above. Tap a county for its daily tick-risk detail.
| County | Deer tick | American dog tick | Lone star tick |
|---|---|---|---|
| Adams County | Established | Established | Not established |
| Ashland County | Established | Established | Not established |
| Barron County | Established | Established | Not established |
| Bayfield County | Established | Established | Not established |
| Brown County | Established | Established | Not established |
| Buffalo County | Established | Established | Not established |
| Burnett County | Established | Established | Not established |
| Calumet County | Established | Established | Not established |
| Chippewa County | Established | Established | Not established |
| Clark County | Established | Established | Not established |
| Columbia County | Established | Established | Not established |
| Crawford County | Established | Established | Not established |
| Dane County | Established | Established | Not established |
| Dodge County | Established | Established | Not established |
| Door County | Established | Established | Not established |
| Douglas County | Established | Established | Not established |
| Dunn County | Established | Established | Not established |
| Eau Claire County | Established | Established | Not established |
| Fond du Lac County | Established | Established | Not established |
| Forest County | Established | Established | Not established |
| Grant County | Established | Established | Not established |
| Green County | Established | Established | Not established |
| Green Lake County | Established | Established | Not established |
| Iowa County | Established | Established | Not established |
| Iron County | Established | Established | Not established |
| Jackson County | Established | Established | Not established |
| Jefferson County | Established | Established | Not established |
| Juneau County | Established | Established | Not established |
| Kenosha County | Established | Established | Not established |
| Kewaunee County | Established | Established | Not established |
| La Crosse County | Established | Established | Not established |
| Lafayette County | Established | Established | Not established |
| Langlade County | Established | Established | Not established |
| Lincoln County | Established | Established | Not established |
| Manitowoc County | Established | Established | Not established |
| Marathon County | Established | Established | Not established |
| Marinette County | Established | Established | Not established |
| Marquette County | Established | Established | Not established |
| Milwaukee County | Established | Established | Not established |
| Monroe County | Established | Established | Not established |
| Oconto County | Established | Established | Not established |
| Oneida County | Established | Established | Not established |
| Outagamie County | Established | Established | Not established |
| Ozaukee County | Established | Established | Not established |
| Pepin County | Established | Established | Not established |
| Pierce County | Established | Established | Not established |
| Polk County | Established | Established | Not established |
| Portage County | Established | Established | Not established |
| Price County | Established | Established | Not established |
| Racine County | Established | Established | Not established |
| Richland County | Established | Established | Not established |
| Rock County | Established | Established | Not established |
| Rusk County | Established | Established | Not established |
| Sauk County | Established | Established | Not established |
| Sawyer County | Established | Established | Not established |
| Shawano County | Established | Established | Not established |
| Sheboygan County | Established | Established | Not established |
| St. Croix County | Established | Established | Not established |
| Taylor County | Established | Established | Not established |
| Trempealeau County | Established | Established | Not established |
| Vernon County | Established | Established | Not established |
| Vilas County | Established | Established | Not established |
| Walworth County | Established | Established | Not established |
| Washburn County | Established | Established | Not established |
| Washington County | Established | Established | Not established |
| Waukesha County | Established | Established | Not established |
| Waupaca County | Established | Established | Not established |
| Waushara County | Established | Established | Not established |
| Winnebago County | Established | Established | Not established |
| Wood County | Established | Established | Not established |
Nymph deer ticks are the size of a poppy seed and cause most Lyme cases in Wisconsin because they are so easy to miss. When you check for ticks, look for the small ones too, especially in June and July.