Background & Aims We sought to estimate the incidence, prevalence and racial-ethnic distribution of physician-diagnosed inflammatory bowel disease (IBD) in the United States. Methods The study utilized four administrative claims datasets: a 20% random sample of national fee for service Medicare data (2007 to 2017); Medicaid data from Florida, New York, Pennsylvania, Ohio and California (1999 to 2012); and commercial health insurance data from Anthem beneficiaries (2006 to 2018) and Optum’s de-identified Clinformatics Data Mart (2000 to 2017). We used validated combinations of medical diagnoses, diagnostic procedures and prescription medications to identify incident and prevalent diagnoses. We computed pooled age-, sex- and race-specific insurance-weighted estimates and pooled estimates standardized to 2018 United States census estimates with 95% confidence intervals (CI). Results The age- and sex-standardized incidence of IBD per 100,000 person-years was 10.9 (95% CI 10.6 – 11.2). The incidence of IBD peaked in the third decade of life, decreased to a relatively stable level across the 4th to 8th decades, and declined further. The age-, sex- and insurance-standardized prevalence of IBD was 721 per 100,000 population (95% CI 717 – 726). Extrapolated to the 2020 census, there is an estimated 2.39 million Americans diagnosed with IBD. The prevalence of IBD per 100,000 population was 812 (95% CI 802 – 823) in White, 504 (482-526) in Black, 403 (373 – 433) in Asian and 458 (440-476) in Hispanic Americans. Conclusions IBD is diagnosed in more than 0.7% of Americans. The incidence peaks in early adulthood and then plateaus at a lower rate. The disease is less commonly diagnosed in Black, Asian and Hispanic Americans.