We know little about first-episode psychosis epidemiology beyond cities or when measured through early intervention in psychosis services. We present results from 18 months of the 3-year Social Epidemiology of Psychoses in East Anglia (SEPEA) study of incepted incidence observed through five early intervention services. We identified 378 eligible individuals (incidence: 45.1/100 000 person-years, 95% CI 40.8-49.9). Rates varied across these services, but were 2-3 times higher than those on which services were commissioned. Risk decreased with age, was nearly doubled among men and differed by ethnic group; doubled in people of mixed ethnicity but lower for those of Asian origin, compared with White British people. Psychosis risk among ethnic minorities was lower than reported in urban settings, which has potential implications for aetiology. Our data suggest considerable psychosis morbidity in diverse, rural communities.