Figure 1: Estimated geographic distribution of American dog ticks (above) and Rocky Mountain wood ticks (below)

2 maps of the United States.  The top map shows where in the U.S. is the American Dog Tick located.  The entire eastern half of the country as well as California are highlighted.  The bottom map shows where the Rocky Mountain Wood Tick can be found.  The North West part of the U.S. is highlighted.

Rocky Mountain spotted fever is a serious tickborne illness which can be deadly if not treated early. It is spread by several species of ticks in the United States, including the American dog tick (Dermacentor variabilis) pdf icon[PDF – 1 page], Rocky Mountain wood tick (Dermacentor andersoni) pdf icon[PDF – 1 page], and, in parts of the southwestern United States and Mexico, the brown dog tick (Rhipicephalus sanguineus) pdf icon[PDF – 1 page]. RMSF cases occur throughout the United States, but are most commonly reported from North Carolina, Tennessee, Missouri, Arkansas, and Oklahoma.