Ticks in Pennsylvania

Written by Phillip George · Last updated: July 24, 2026

Ticks in Pennsylvania: what to actually watch for

Pennsylvania reports more Lyme disease cases than any other US state, year after year, and blacklegged ticks have been confirmed in all 67 counties. The flip side of that grim statistic is that Pennsylvania offers one of the best free resources in the country: any PA resident can mail in a tick and have it tested for pathogens at no cost. This guide covers the species, the risk picture, and how to use that testing program.

Key takeaways for Pennsylvania

• Highest Lyme burden in the US: Pennsylvania consistently leads the nation in reported Lyme cases, and blacklegged ticks are established statewide.
• Free tick testing: the PA Tick Research Lab at East Stroudsburg University tests ticks for free for Pennsylvania residents.
• More than Lyme: the same tick also spreads anaplasmosis and babesiosis, and lone star and Asian longhorned ticks are now present too.

Which ticks you'll actually encounter

• Blacklegged / deer tick (Ixodes scapularis) — by far the most important, present in all 67 counties and responsible for Lyme, anaplasmosis, and babesiosis. Nymphs (May–July) cause most human cases.
• American dog tick (Dermacentor variabilis) — common in grassy areas; a nuisance biter.
• Lone star tick (Amblyomma americanum) — expanding, especially in southern PA; can cause ehrlichiosis and alpha-gal syndrome.

Source: PA Department of Health — Tick diseases.

Where and when risk is highest

Because blacklegged ticks are established in every county, no part of Pennsylvania is risk-free. Wooded and brushy areas, field edges, and leaf litter are the highest-exposure spots. Adults are active in spring and fall (and on mild winter days), while the tiny, hard-to-spot nymphs peak from late spring through midsummer — the period responsible for most infections.

Tick-borne diseases reported in Pennsylvania

• Lyme disease — the dominant tick-borne illness; PA leads the US in reported cases.
• Anaplasmosis and babesiosis — increasing, from the same blacklegged tick.
• Spotted fever group and ehrlichiosis — less common, linked to dog ticks and lone star ticks.

For symptoms and timelines, see our tick-borne disease symptoms in humans guide.

Found a tick in Pennsylvania? Do this

1. Remove it promptly with fine-tipped tweezers — follow our tick removal guide. Save the tick in a bag or container.
2. Get it tested for free: Pennsylvania residents can submit the tick to the PA Tick Research Lab (ticklab.org) at East Stroudsburg University, which tests for Lyme and other pathogens at no cost (results typically within about 72 business hours).
3. Record the date and location and monitor for a rash or flu-like symptoms for several weeks.
4. Contact a healthcare provider if symptoms develop — a positive tick test is useful context but does not replace medical evaluation.

Official Pennsylvania resources

• PA Department of Health — Lyme disease
• PA Department of Health — Tick diseases
• PA Tick Research Lab (ESU) — free tick testing for PA residents
• CDC — What to do after a tick bite

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