Exotic tick species and tick-borne diseases are serious threats to live-stock, companion animals, and wildlife in the United States. Recurring introductions of exotic tick species into the United States are a significant indicator of the degree of risk. Successful tick-eradication campaigns, such as the national program that eradicated Boophilus annulatus and B. microplus from the United States, the Cattle Fever Tick Eradication Program of the US Department of Agriculture's Veterinary Services that protects against the re-entry and dissemination of Boophilus ticks from Mexico back into their former haunts in the southern states, and the eradication action that eliminated Rhipicephalus evertsi from a game park in Florida, are sources of useful information that aid in elucidating essential elements of successful eradication programs. Examples of failed eradication programs in places such as Puerto Rico and St. Croix also have heuristic value. Among the varieties of tick species and related infectious agents that threaten the United States, Boophilus ticks and bovine babesiosis, Amblyomma species (especially the tropical bont tick) and heartwater, and equine babesiosis, for which endemic vectors exist, are of special concern. Risk assessments to accumulate, evaluate, and synthesize information needed to appraise risks, consequences, and preparedness are necessary not just to inform federal, state, and local officials, as well as producers and stakeholders, but also to facilitate the creation of emergency response plans.