To determine the prevalence and diversity of Leptospira serogroups circulating in wildlife on farms in Ontario, we tested samples from 51 raccoons (Procyon lotor), seven skunks (Mephitis mephitis), four rats (Rattus norvegicus), and three opossums (Didelphis virginiana) that were trapped on 27 livestock (swine [Sus scrofa], cattle [Bos taurus]) farms in 2010. Seventeen of 51 raccoons (33%; 95% confidence interval [CI], 21–48%) sampled were positive for at least one Leptospira serogroup using the microscopic agglutination test. None of the other 14 animals had detectable Leptospira antibodies. On swine farms, 13 of 30 raccoons (43%; 95% CI, 27–61%) were antibody positive, and on cattle farms, four of 21 raccoons (19%; 95% CI, 8–40%) were positive. Leptospira antibody prevalence in raccoons did not differ between swine and cattle farms. Raccoons were positive to serovars representative of serogroups Grippotyphosa, Australis, Icterohaemorrhagiae, and Pomona and were negative to serovars of serogroups Autumnalis, Canicola, and Sejroe. The prevalence of Leptospira antibodies in raccoons in this study is similar to what has been reported previously; however, the diversity of serogroups was higher in this study than what has been reported in raccoons from an urban area of Ontario, Canada. Understanding the prevalence and distribution of Leptospira serogroups in wildlife in Ontario, Canada, is important for the development and maintenance of appropriate disease management strategies in humans, livestock, and companion animals.