Counties in the U.S. with TickSpotters reports of Western blacklegged ticks (Ixodes pacificus) from 2014 to 2019 that were not reported to have Western blacklegged ticks in county data compiled in previous research. Black represents the species as “reported” and grey represents the species as “established.” (Image orginally published in Kopsco et al 2021, Journal of Medical Entomology)