You may encounter ticks in Colorado, especially along grassy trail edges, shrubs, forest margins, and foothill paths. Colorado has about 28 to 30 recorded tick species, with the Rocky Mountain wood tick and American dog tick among the most common.
Tick activity often peaks in spring and early summer. Mild weather can keep ticks active beyond those months.
You can greatly reduce your risk by using repellent, wearing protective clothing, checking your skin and pets after outdoor activities, and removing attached ticks promptly with fine-tipped tweezers. Most tick bites do not cause illness, but Colorado ticks can transmit Colorado tick fever, tick-borne relapsing fever, tularemia, and other infections.
The Colorado Department of Public Health and Environment’s tick-borne illness guidance identifies American dog ticks, Rocky Mountain wood ticks, and brown dog ticks as locally relevant species.
Colorado Tick Activity, Season, And Habitat
Colorado’s tick season is strongest during warm, moist periods in spring and early summer. You can still encounter ticks at other times, including during mild winter days.
Elevation does not guarantee protection because ticks may live near 10,000 feet.
When Tick Season Peaks In Colorado
Tick activity commonly rises from March through June, when adult ticks seek hosts in vegetation. Activity may continue through summer and fall, particularly after rain or during stretches of mild weather.
As UCHealth’s Colorado tick guidance explains, ticks can remain active throughout the year.
Where Exposure Is Most Likely
You are most likely to encounter ticks where grasses, shrubs, and low branches meet a trail. Common habitat includes foothills, mountain valleys, forest edges, brushy campsites, and areas used by deer, rodents, dogs, and other hosts.
Ticks do not usually drop from trees. They climb grass or low vegetation and attach when you brush past.
Staying near the center of a maintained trail can reduce contact, though it does not eliminate risk.
How Weather And Elevation Affect Risk
Warm temperatures can increase movement and host-seeking activity. Moist ground cover may also support ticks, while prolonged hot, dry conditions can reduce activity in exposed areas.
High elevation is not a reliable safeguard. Rocky Mountain wood ticks live in high-elevation environments, so you should continue prevention on mountain hikes and camping trips.
The Tick Species That Matter Locally
Colorado has many tick species, but only a smaller group commonly affects people, pets, wildlife, or livestock. Species identification can be difficult because ticks change appearance as they mature and feed.
Rocky Mountain Wood Tick And American Dog Tick
The Rocky Mountain wood tick, Dermacentor andersoni, is strongly associated with Colorado’s mountain regions and can transmit Colorado tick fever, tularemia, and other pathogens. It is also linked to tick paralysis in rare situations.
The American dog tick, Dermacentor variabilis, occurs in many parts of the United States and can bite people and pets in Colorado. It may transmit tularemia and Rocky Mountain spotted fever, although these illnesses are not frequently reported in the state.
Dog, Wildlife, And Cabin-Associated Ticks
The brown dog tick, Rhipicephalus sanguineus, mainly infests dogs, kennels, homes, and animal housing. Unlike many outdoor ticks, it can complete parts of its life cycle indoors.
Other recorded species include the winter tick, Dermacentor albipictus, which primarily affects large wildlife; the rabbit tick, Haemaphysalis leporispalustris; and the ear tick, Otobius lagophilus. Soft ticks such as Ornithodoros hermsi can inhabit rustic cabins and are associated with tick-borne relapsing fever.
Ticks More Often Linked To Travel Or Isolated Reports
The lone star tick, Amblyomma americanum, the deer or blacklegged tick, Ixodes scapularis, and the western blacklegged tick, Ixodes pacificus, are more strongly associated with regions outside Colorado. Occasional records or travel-related exposures do not mean these are the dominant local ticks.
Lyme disease in Colorado is uncommon from in-state exposure because established populations of the principal Lyme vector are limited. Travel, expanding ranges, and occasional findings mean you should report recent destinations when discussing a tick bite with a clinician.
The Colorado Tick-Borne Disease Awareness Association’s species information notes that 28 tick species are currently known in the state.
Disease Risk After A Colorado Tick Bite
A tick bite does not automatically mean you will become sick. Risk depends on the tick species, pathogen prevalence, attachment, location, season, and how long the tick fed.
Colorado Tick Fever, Rocky Mountain Spotted Fever, And Tularemia
Colorado tick fever is a viral illness most often spread by an infected Rocky Mountain wood tick. The Centers for Disease Control and Prevention describes its link to Dermacentor andersoni.
Fever, chills, headache, fatigue, and body aches may appear several days after a bite. Tularemia and Rocky Mountain spotted fever are bacterial illnesses that can occur after exposure to infected ticks, though Rocky Mountain spotted fever is rare in Colorado.
Tick-borne relapsing fever is another concern, especially after exposure to soft ticks in rustic mountain cabins.
Why Lyme Disease Is Uncommon From In-State Exposure
Lyme disease is common in parts of the Northeast, Midwest, and Pacific Coast, yet confirmed in-state transmission in Colorado is uncommon. Many Colorado cases involve travel to areas where infected blacklegged ticks are established.
You should not dismiss symptoms solely because a bite occurred in Colorado. A clinician may consider travel history, tick appearance, symptoms, and other possible tick-borne diseases.
When To Contact A Clinician
Contact a clinician if you develop fever, severe headache, chills, unusual fatigue, muscle or joint pain, swollen lymph nodes, a spreading rash, or worsening symptoms within days or weeks of a bite. Mention the date and location of exposure, recent travel, outdoor activities, and whether you saved the tick.
Pets can also become ill. Fever, lethargy, limping, appetite loss, or swollen lymph nodes warrant a call to your veterinarian.
Preventing Bites And Removing Ticks Safely
You can lower exposure by combining a registered tick repellent with protective clothing and consistent tick checks. Prevention matters in yards, parks, foothills, mountain valleys, and high-elevation recreation areas.
Repellents And Protective Clothing
Use an EPA-registered tick repellent containing DEET, picaridin, or oil of lemon eucalyptus according to the label. Apply repellent to exposed skin as directed, and never use products formulated for clothing directly on skin.
For hiking or camping, wear long pants, long sleeves, tall socks, and light-colored clothing. Tuck pants into socks when practical.
Permethrin-treated clothing and gear can provide additional protection. Permethrin products should be used only as labeled and not applied to skin.
Tick Checks For People And Pets
After being outdoors, inspect your clothing, skin, hair, and gear. Pay close attention to the scalp, hairline, ears, waistband, armpits, groin, navel, and backs of the knees.
Showering soon after returning indoors can help remove unattached ticks. Put outdoor clothing in a hot dryer for about 20 minutes before washing when appropriate.
Check dogs and other pets, especially around the ears, collar, toes, and between the legs. Use only veterinarian-approved products, since some dog tick treatments are toxic to cats.
Correct Tick Removal And Follow-Up
Grasp the tick as close to your skin as possible using fine-tipped tweezers. Pull upward with steady, even pressure.
Clean the bite area and your hands with soap and water or an antiseptic. Do not twist, crush, burn, or coat the tick with petroleum jelly, nail polish, alcohol, or other substances.
If you cannot remove mouthparts easily, clean the area and seek medical advice. Note the date and location of the bite.
Save the tick in a sealed container if possible. Monitor your health for several weeks.
