Mosquito-borne Cache Valley virus (CVV), from the Orthobunyavirus family, causes disease in humans and animals. First discovered in Canada in 1971, CVV is now considered endemic throughout the country. Cache Valley virus disease (CVVD) is most reported in sheep as fatal congenital deformities in lambs when dams are infected in early pregnancy. In humans, cases are rarely reported, but surveillance is passive and CVVD is not notifiable. Under-reporting of CVVD in humans, as well as animals contributes to poor understanding of the epidemiology of CVV. This thesis aimed to characterize the epidemiology of CVV in Ontario, Canada by: 1) describing the contemporary knowledge of CVV epidemiology in North America in the context of host and vector species, 2) assessing CVV seropositivity and associated farm management risk factors in sheep flocks in Ontario, and 3) identifying spatiotemporal patterns of CVV vectors in Ontario from 2002 to 2020. Through two scoping reviews, important knowledge gaps relevant to Canada were highlighted, including the absence of routine CVV testing in mosquito or animal populations, limited risk factor analysis associated with host and vector infections, and no research on CVVD modeling or risk mapping in the context of climate change. Through a cross-sectional study, widespread CVV exposure was documented across farms in southern Ontario, with one in three ewes being seropositive. Risk factors associated with higher odds of CVV seropositivity included increased age, sheep housing near natural bodies of stagnant water, and smaller flock size, which is likely a proxy for housing. These findings can guide breeding and housing practices during mosquito season to minimize exposure and, ultimately, CVVD in the flock. Lastly, the spatiotemporal study identified patterns of seasonal emergence, peak abundance, and decline for CVV vectors across Ontario, corresponding to peak CVV loads reported in mosquitoes and CVVD incidence in humans and livestock. These findings highlight the at-risk critical period within a season and geographic regions in Ontario, thereby guiding public and animal health efforts in controlling CVV exposure and mitigating disease.