Timely reporting of animal diseases is fundamental to the detection of emerging threats, rapid and effective outbreak response, and ultimately the health of both animals and humans. In the United States, each state has the authority to regulate reporting of diseases. While past research has reviewed reportable human diseases, the research on reportable animal diseases has assessed only veterinarian knowledge and understanding of law rather than identifying the actual statutes and regulation that exists. Therefore, this article reviewed the statutes, regulations, and online reportable animal disease lists from the 50 states and District of Columbia to describe the legal landscape of animal disease reporting. The findings suggest wide variation in state animal disease reporting requirements. Three hundred and forty distinct diseases, agents, and categories were identified, with only 15 diseases being listed by 40 or more states. States typically require reporting of animal diseases within 48 h. Substantial consideration needs to be given to the implications of these variations for rapid and effective animal and zoonotic disease detection and reporting in the United States, particularly in light of One Health initiatives and international obligations.