Allendale Columbia School (often shortened to Allendale Columbia or abbreviated as A.C.) is an independent, nonsectarian, college preparatory school for students in nursery through twelfth grade in Rochester, New York, USA. The Columbia School for girls, established in 1890 by Caroline Milliman and Alida Lattimore, and the Allendale School for boys, established in 1926 by a group of Rochester businessmen, merged in 1972 to form the current co-educational school. Allendale Columbia students come from 28 different school districts in the greater Rochester, New York region, as well as from 10 different countries. International students live in two houses on campus. The school was named by Worth magazine as of one of the top 100 feeder schools to Ivy League universities. It was also ranked as the best private high school in Monroe County by Niche and The Post-Standard. Newsweek named Allendale Columbia as one of the best STEM schools in America.