At a glance
- The western blacklegged tick (Ixodes pacificus) is found along the Pacific coast of the United States, particularly northern California.
- Larvae and nymphs often feed on lizards, birds, and rodents, and adults more commonly feed on deer.
- Nymphs and adult females are more often reported on people, but larvae also bite people.
Map
Map of the United States showing projected suitable habitat for Ixodes pacificus ticks and counties with established Ixodes pacificus populations through 2025.
To access the data used for these maps go to data sets.
A note about established status
An established county means six or more blacklegged ticks of a single life stage or more than one life stage of blacklegged tick was collected in a county within a 12-month period. A county that is not labeled as established does not mean ticks are absent. Once a tick species is recorded as established within a county, the status will remain "established" in subsequent years.