Purpose: To determine the population-based incidence and disease associations of episcleritis and scleritis in a midwestern U.S. population. Design: Population-based retrospective cohort study. Methods: All residents of Olmsted County, Minnesota from 2006 to 2015 were identified by using the Rochester Epidemiology Project. A total of 223 episcleritis cases and 77 scleritis cases were identified. The incidence and disease associations of episcleritis and scleritis were assessed, as well as scleritis recurrence rates, treatment, and complications. Results: Incidence rates for episcleritis and scleritis were 15.39 and 5.54 per 100,000 per year, respectively. Females accounted for 60.1% of episcleritis and 51.9% of scleritis cases. The mean age at diagnosis was 40.2 years of age for episcleritis and 48.8 years of age for scleritis. In the episcleritis cases, the incidence in females was higher (P =.01). There were no significant differences between sexes for scleritis incidence (P =.75); 23.4% of scleritis patients had an associated systemic disease. Patients with systemic disease showed a trend toward an increased risk of recurrence, but it was not statistically significant. There was a slightly decreased risk of scleritis recurrence with older age at diagnosis (hazard ratio [HR]: 0.73; P =.058; 95% confidence interval [CI]: 0.52-1.01). At last follow-up, most eyes with scleritis (90.4%) had good visual acuity (better than 20/40), and 92.3% had stable or improved visual acuity. Conclusions: The Olmsted County, Minnesota population had a lower incidence of episcleritis and a higher incidence of scleritis than populations in previous studies. The population-based results from the current study may provide information that is more applicable to a primary eye care setting.