Deerfield Academy is an independent, coeducational boarding school at Deerfield, Massachusetts, United States. It is a four-year college-preparatory school with approximately 640 students and about 120 faculty, all of whom live on or near campus during the school year. Deerfield is a member of the Eight Schools Association (ESA), begun informally in 1973–74 and formalized in 2006, and of the Ten Schools Admissions Organization, founded in 1956. There is a seven-school overlap of membership between the two groups. Deerfield is additionally a member of the G20 Schools group.