Two types of dog ticks are common in the United States, the American dog tick, appropriately, and the brown dog tick. Both of these species feed mostly on wild, small mammals, but your dog can pick up a tick just as easily as a wild rat or bunny can.
American Dog Tick
The American dog tick is most common in the eastern half of the United States. If you were to draw a line from Montana down through Texas, you'll find the American dog tick on the entire right half of the country. But it can be found in limited areas of the western United States to include Iowa, Minnesota, California, west of the Cascade and in the Sierra Nevada Mountain ranges. The American dog tick is most responsible for transmitting the pathogen that causes Rocky Mountain spotted fever; it can also transmit tularemia -- which can cause canine tick paralysis -- and babesiosis -- which can cause anemia.
Brown Dog Tick
The brown dog tick is not specific to a certain area; it is common around the entire country. It can cause canine ehrlichiosis, canine bartonellosis and Hepatozoonosis. Like the American dog tick, the brown dog tick can transmit tularemia and babesiosis.