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Ticks in Indiana

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 Indiana county
Blacklegged tick activity by Indiana county
ISDH surveillance · 2024-2025 season
Source: ISDH + Purdue Extension + BOAH + CDC TickNET (placeholder baseline; awaiting ISDH county-level import. IN is an active multi-tick frontier)

Common species in Indiana

Indiana 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

When ticks are most active

Broad caution April through October. American dog tick peaks spring-summer; lone star tick activity May-August; blacklegged tick nymphs peak May-July (northern + southern IN). Indiana is genuinely a multi-tick frontier with both Midwest expansion patterns visible.

Status:source caveated editorial

Where you're most likely to encounter ticks

Brown County + Hoosier National Forest, Indiana Dunes National Park, Turkey Run + Shades State Parks, Patoka Lake, Indianapolis + Fort Wayne + Evansville suburban edges, Purdue + Bloomington area trails, 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.

  • Ehrlichiosisstate surveillance confirmed
  • Rocky Mountain spotted feverstate surveillance confirmed
  • Lyme diseasestate surveillance confirmed

    ISDH publishes Lyme surveillance; northern + southern IN counties lead. Indiana is a Lyme-expansion frontier

  • Anaplasmosisstate surveillance confirmed
  • Alpha-gal syndromeregional pattern

    Lone star expansion + IN in the watch zone

  • Babesiosisnon diagnostic mention only
  • Powassan virus diseasenon diagnostic mention only

If you find a tick — what to do

Tick-ID program status:state id program uncertain

Map resolution notes

mixed resolution.ISDH publishes county-level data supporting county-resolution claims. Indiana is an active expansion zone — county-resolution data is genuinely useful because risk varies between southern (lone star + blacklegged corridor), central (mixed), and northern (lake-effect, blacklegged). Purdue Extension covers ecoregion-resolution. CDC maps support national comparison.

State sources

Primary species source
Indiana State Department of Health (ISDH) Zoonotic Diseases + Tickborne Diseases hub; Purdue University Extension entomology publications.
Primary health source
ISDH Zoonotic Diseases tickborne disease surveillance + reportable disease summaries; CDC pages and maps for national guardrails.
Primary extension source
Purdue Extension publications on Indiana tick species, life cycles, lone star + blacklegged expansion, and yard/property tick management.
Surveillance
ISDH county-level tickborne disease surveillance; Indiana Board of Animal Health (BOAH) animal-health + Asian longhorned tick monitoring; Purdue University entomology; CDC for national comparison.