The Tick Almanac
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Ticks in Maryland

Common species, seasonal activity, exposure scenarios, what to do after a bite, and the state’s tick-identification options. Sourced from the state health department + university extension.

STATE COUNTY RANGE MAP
rendered 2026-05-25
Blacklegged tick activity by Maryland county
Blacklegged tick activity by Maryland county
MDH surveillance · 2024-2025 season
Source: MDH + UMD Extension + MDA + CDC TickNET (placeholder baseline; awaiting MDH county-level import)

Common species in Maryland

Maryland follows the state health led source pattern. The species below are drawn from the state-authority sources listed in the sidebar Data Row.

III
4-6 mm
Macro photo of an unfed adult american dog tick with a millimeter scale
American dog tick
Dermacentor variabilis
Identify →
IV
4-6 mm
Macro photo of an unfed adult lone star tick with a millimeter scale
Lone star tick
Amblyomma americanum
Identify →
V
3-4 mm
Macro photo of an unfed adult brown dog tick with a millimeter scale
Brown dog tick
Rhipicephalus sanguineus
Identify →
SECONDARY
EMERGING WATCH
  • Asian longhorned tick (MDA + MDH surveillance — established in multiple MD counties)

When ticks are most active

Broad caution April through October. Blacklegged tick nymphs peak May-July; lone star tick activity May-August (statewide and a major AGS driver); American dog tick spring-summer. Maryland has high Lyme incidence, especially in central + western counties.

Status:source caveated editorial

Where you're most likely to encounter ticks

Catoctin Mountain + Western Maryland hiking, Patapsco Valley State Park, Chesapeake Bay shoreline + Eastern Shore, Montgomery + Howard County suburban edges, Baltimore-area parks (Patapsco, Soldiers Delight), Assateague Island, hunting properties statewide, dog walking in any wooded or tall-grass edge.

Disease context

Each disease named below carries an evidence tag per the Data Row policy. Pills indicate the strength of state-specific evidence, not the severity of the disease. Symptoms should always be routed to a clinician; this is orientation, not diagnosis.

  • Lyme diseasestate surveillance confirmed

    MDH publishes Lyme surveillance; central + western MD counties have high per-capita rates

  • Anaplasmosisstate surveillance confirmed
  • Babesiosisstate surveillance confirmed
  • Ehrlichiosisstate surveillance confirmed
  • Rocky Mountain spotted feverstate surveillance confirmed
  • Powassan virus diseasestate surveillance confirmed
  • Alpha-gal syndromestate unique angle

    MD is in the documented AGS high-incidence cluster (lone star territory)

  • STARIregional pattern
  • Tularemianon diagnostic mention only

If you find a tick — what to do

Tick-ID program status:state id program uncertain

Map resolution notes

mixed resolution.MDH publishes county-level Lyme + tickborne disease data supporting county-resolution claims. UMD Extension covers ecoregion-resolution (Appalachian Plateau vs Piedmont vs Coastal Plain). Asian longhorned tick distribution actively updated by MDA. CDC maps support national comparison.

State sources

Primary species source
Maryland Department of Health (MDH) Center for Zoonotic and Vector-Borne Diseases + Tick-Borne Diseases hub; University of Maryland Extension entomology publications.
Primary health source
MDH Center for Zoonotic and Vector-Borne Diseases tickborne disease surveillance + reportable disease summaries; CDC pages and maps for national guardrails.
Primary extension source
University of Maryland Extension (UMD Extension) + UMD entomology publications on MD tick species and yard/property tick management.
Surveillance
MDH county-level Lyme + tickborne disease surveillance; Maryland Department of Agriculture (MDA) animal-health + Asian longhorned tick monitoring; UMD entomology + the Mid-Atlantic Center of Excellence in Vector-Borne Diseases (CDC-funded, Cornell-led with UMD participation); CDC for national comparison.