Tick Season 2025: This Might Be Illinois’ Worst Ever–Here’s Why

In the interests of full disclosure, I'll have to admit to never having been bitten by a tick (that I know of, anyway), and I can't recall one ever burrowing into my skin, either. I've had to deal with leeches after swimming in a local creek, but that's a gross and uncomfortable story for another day.

Even though I've not had a personal encounter with one of Illinois' many varieties of ticks, my coworker Joe has had to deal with them a half-dozen times so far this spring season--and from what I've been reading, he is far from being alone. People are reporting huge numbers of ticks all over Northern Illinois.

Illinois has thirteen different species of tick living within our state, but only around six of those of regularly seen by human beings. According to the Illinois Department of Natural Resources (IDNR), these are the tick species you're most likely to encounter:

1. American dog tick (Dermacentor variabilis)

2. Brown dog tick (Rhipicephalus sanguineus)

3. Black-legged or deer tick (Ixodes scapularis)

4. Gulf Coast tick (Amblyomma maculatum)

5. Lone star tick (Amblyomma americanum)

6. Winter tick (Dermacentor albipictus)

Reports Of Huge Tick Populations Are Happening All Over Northern Illinois, Far More Than We've Seen In Previous Years

Here are just a few examples of those reports, courtesy of Patch.com:

• On social media, one person commented that "ticks are absolutely awful this year," while someone else said they'd "never seen so many ticks in May before."
• One woman shared that she took her dog for a walk at Silver Springs State Fish and Wildlife Area in Kendall County and found five ticks embedded in his fur when they returned home.
• A Reddit user said their child was "swarmed" by them and "covered in ticks" after waking at Morton Arboretum in Lisle.
• Oswego Animal Hospital corroborated the increase in sightings. In a post on Facebook, staff warned residents that the arachnids pose a "serious risk" to pets and recommended dogs are on year-round flea and tick prevention.

It's Hard To Believe That Something That Small Could Be So Dangerous--But They Are

It's not like they'll drain you of your entire blood supply, like a tiny little vampire. It's what happens when they're feeding on your or your pet. While a tick feeds, it can also transmit any diseases it may be carrying directly into the bloodstream of the host. They can also jump from host to host.

According to TurfCareOnline.com, here's what Illinois' most common ticks can transmit to you, its host:

American Dog Tick: Also known as the wood tick, this is the most common tick in Illinois. Most active in April through June, the American dog tick has been known to transmit Rocky Mountain spotted fever and ehrlichiosis.

Lone Star Tick: The Lone Star tick is a small (1/8 an inch long), brown tick found mostly in southern Illinois. Active in April through July, the Lone Star tick can transmit Rocky Mountain spotted fever as well as other bacterial infections.

Blacklegged Tick: Known as the deer tick, this is an active tick reddish-brown in color and growing to 1/8 an inch in length.  It is known to transmit Lyme disease and ehrlichiosis to humans.

Brown Dog Tick: Also known as the kennel tick, this species only infects dogs. It is not usually found outdoors in Illinois; rather, it is transmitted indoors from dog to dog, like at a kennel or breeder.