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
Tick Identification in Wisconsin
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.
Carries Lyme
American dog tick
Dermacentor variabilis
Established in Wisconsin
- Size:
- Larger, an apple seed
- Look for:
- Brown with an ornate off-white mottled shield
- Carries:
- Rocky Mountain spotted fever, tularemia (rare)
Lone star tick
Amblyomma americanum
Established in Wisconsin
- Size:
- Medium, rounded
- Look for:
- Reddish-brown; female has a single white dot on the back
- Carries:
- Ehrlichiosis, STARI, alpha-gal syndrome
Brown dog tick
Rhipicephalus sanguineus
Found nationwide, the one tick that infests homes and kennels indoors
- Size:
- Medium, narrow body that tapers toward the head
- Look for:
- Uniform reddish-brown, no ornate markings
- Carries:
- Rocky Mountain spotted fever, canine diseases
Gulf Coast tick
Amblyomma maculatum
A southern tick spreading north into the mid-Atlantic
- Size:
- Large, bigger than a lone star
- Look for:
- Silvery ornate markings on the shield, no single dot
- Carries:
- Rickettsia parkeri spotted fever
Asian longhorned tick
Haemaphysalis longicornis
A newer arrival, established in the mid-Atlantic and spreading north
- Size:
- Small and plain, often found in large numbers
- Look for:
- Reddish-brown with no markings
- Carries:
- Mainly a livestock threat; human disease risk under study
Rocky Mountain wood tick
Dermacentor andersoni
Not established in Wisconsin
- Size:
- Larger, an apple seed
- Look for:
- Brown with an ornate off-white and gray marbled shield
- Carries:
- Rocky Mountain spotted fever, Colorado tick fever, tularemia
Pacific Coast tick
Dermacentor occidentalis
Not established in Wisconsin
- Size:
- Larger, an apple seed
- Look for:
- Brown with a marbled silvery-gray ornate shield
- Carries:
- Pacific Coast tick fever, tularemia
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.
Deer, dog and lone star ticks by Wisconsin county
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 | Not established | Not established |
| Bayfield County | Established | Established | Not established |
| Brown County | Established | Not established | Reported |
| Buffalo County | Established | Reported | Not established |
| Burnett County | Established | Not established | Not established |
| Calumet County | Not established | Not established | Not established |
| Chippewa County | Established | Reported | Not established |
| Clark County | Established | Established | Not established |
| Columbia County | Established | Established | Reported |
| Crawford County | Established | Not established | Not established |
| Dane County | Established | Established | Established |
| Dodge County | Reported | Not established | Reported |
| Door County | Established | Not established | Reported |
| Douglas County | Established | Established | Reported |
| Dunn County | Established | Established | Not established |
| Eau Claire County | Established | Established | Reported |
| Florence County | Reported | Reported | Not established |
| Fond du Lac County | Established | Reported | Not established |
| Forest County | Established | Not established | Not established |
| Grant County | Established | Not established | Not established |
| Green County | Established | Not established | Not established |
| Green Lake County | Established | Established | Not established |
| Iowa County | Established | Established | Reported |
| Iron County | Not established | Established | Not established |
| Jackson County | Established | Established | Reported |
| Jefferson County | Established | Reported | Reported |
| Juneau County | Established | Reported | Not established |
| Kenosha County | Established | Reported | Not established |
| Kewaunee County | Not established | Not established | Not established |
| La Crosse County | Established | Not established | Not established |
| Lafayette County | Established | Reported | Not established |
| Langlade County | Established | Reported | Reported |
| Lincoln County | Established | Established | Not established |
| Manitowoc County | Established | Not established | Reported |
| Marathon County | Established | Reported | Not established |
| Marinette County | Established | Not established | Not established |
| Marquette County | Established | Not established | Reported |
| Menominee County | Established | Not established | Not established |
| Milwaukee County | Established | Established | Reported |
| Monroe County | Established | Established | Reported |
| Oconto County | Established | Reported | Not established |
| Oneida County | Established | Established | Not established |
| Outagamie County | Reported | Reported | Not established |
| Ozaukee County | Reported | Not established | Not established |
| Pepin County | Established | Not established | Not established |
| Pierce County | Established | Not established | Not established |
| Polk County | Reported | Not established | Reported |
| Portage County | Established | Reported | Not established |
| Price County | Established | Reported | Reported |
| Racine County | Established | Established | Not established |
| Richland County | Established | Not established | Not established |
| Rock County | Established | Not established | Reported |
| Rusk County | Established | Established | Not established |
| Sauk County | Established | Reported | Reported |
| Sawyer County | Established | Established | Not established |
| Shawano County | Reported | Not established | Not established |
| Sheboygan County | Established | Not established | Reported |
| St. Croix County | Established | Established | Reported |
| Taylor County | Established | Not established | Not established |
| Trempealeau County | Established | Reported | Not established |
| Vernon County | Established | Reported | Reported |
| Vilas County | Established | Established | Reported |
| Walworth County | Established | Established | Reported |
| Washburn County | Established | Established | Not established |
| Washington County | Not established | Not established | Not established |
| Waukesha County | Established | Reported | Reported |
| Waupaca County | Established | Established | Not established |
| Waushara County | Established | Not established | Not established |
| Winnebago County | Reported | Not established | Reported |
| Wood County | Established | Established | Reported |
Lone star ticks and alpha-gal syndrome
The lone star tick is established in Wisconsin, including Dane County. Its bite can cause alpha-gal syndrome, an allergy to red meat.
Do not overlook the tiny ones
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.
Frequently asked questions
- What types of ticks live in Wisconsin?
- Wisconsin has the deer tick (blacklegged tick), which carries Lyme disease and is established across the state; the American dog tick, which is established; and the lone star tick, which is established and causes alpha-gal syndrome. County-level presence is shown in the table above.
- Which Wisconsin tick carries Lyme disease?
- The deer tick, also called the blacklegged tick, is the tick that spreads Lyme disease in Wisconsin. The American dog tick and lone star tick do not carry Lyme, though they can transmit other illnesses.
- Are there lone star ticks in Wisconsin?
- Yes. The lone star tick is established in Wisconsin, including Dane County. It causes alpha-gal syndrome, a red-meat allergy.
- How can I tell these ticks apart?
- Use size, color, and legs. The deer tick is small with a reddish-orange body, a solid dark shield, and black legs. The American dog tick is larger and brown with an ornate off-white mottled shield. The female lone star tick has a single white dot on her back. The chart above shows each one.