Deer tick
Ixodes scapularis
Established in Maryland
- 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 Maryland
The ticks you are most likely to find in Maryland, 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 Maryland
- 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 Maryland
- 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 Maryland
- 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 Maryland
- Size:
- Larger, an apple seed
- Look for:
- Brown with a marbled silvery-gray ornate shield
- Carries:
- Pacific Coast tick fever, tularemia
Maryland 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 Maryland county
These are the three ticks CDC maps county by county, not the only ticks in Maryland: 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 |
|---|---|---|---|
| Allegany County | Reported | Not established | Not established |
| Anne Arundel County | Established | Established | Established |
| Baltimore County | Established | Established | Established |
| Baltimore city | Not established | Reported | Reported |
| Calvert County | Established | Established | Established |
| Caroline County | Established | Established | Established |
| Carroll County | Established | Reported | Reported |
| Cecil County | Established | Established | Established |
| Charles County | Established | Established | Established |
| Dorchester County | Established | Established | Established |
| Frederick County | Established | Established | Established |
| Garrett County | Established | Established | Not established |
| Harford County | Established | Reported | Established |
| Howard County | Established | Established | Established |
| Kent County | Established | Established | Established |
| Montgomery County | Established | Established | Established |
| Prince George's County | Established | Established | Established |
| Queen Anne's County | Established | Established | Established |
| Somerset County | Established | Not established | Established |
| St. Mary's County | Established | Established | Established |
| Talbot County | Established | Established | Reported |
| Washington County | Established | Not established | Reported |
| Wicomico County | Established | Not established | Established |
| Worcester County | Established | Established | Established |
Lone star ticks and alpha-gal syndrome
The lone star tick is established in Maryland in 18 of 24 counties (see the table above). 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 Maryland 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 Maryland?
- Maryland 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 Maryland tick carries Lyme disease?
- The deer tick, also called the blacklegged tick, is the tick that spreads Lyme disease in Maryland. The American dog tick and lone star tick do not carry Lyme, though they can transmit other illnesses.
- Are there lone star ticks in Maryland?
- Yes. The lone star tick is established in Maryland, in 18 of the state's 24 counties (Anne Arundel County, Baltimore County, Calvert County and more, listed in the table above). 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.