The California Institute of Technology was the hardest US school to get into in the 2024-2025 year.

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For some schools across the US, a low single-digit acceptance rate has become shorthand for prestige.With increasingly accomplished high school students competing for limited spots at some of the nation's top universities, a 4.0 GPA may no longer be enough to stand out in a crowded applicant pool. At some elite colleges, admissions have only become more competitive in recent decades.Harvard, for example, received 18,190 applications in 1996, as reported by the school's student newspaper. Only 10.9% of applicants were admitted, which, at the time, was the school's lowest acceptance rate on record.For the Class of 2029, Harvard received 47,893 applications. The college admitted 2,003 students — a similar number of spots for prospective students as it had 30 years ago — for an acceptance rate of 4.2%.Some of the hardest colleges to get into in the US are big-name schools with tens of thousands of students, while others are specialized, curated science or arts programs with only a couple of hundred students.Business Insider looked at the most recent available data from the National Center for Education Statistics' College Navigator and identified the most selective schools in the country that admitted 10% or less of their applicants. These were then ranked from lowest to highest acceptance rate for the 2024-2025 school year.For schools with the same acceptance rate, ties were broken by the number of applicants, with schools that received more applications ranking higher.While the ranking includes some smaller, lesser-known colleges where selectivity is driven by small class sizes and tightly curated curricula, some schools with applicant pools or total student populations of under 100 were excluded from the list as their acceptance rates are not entirely comparable to those of more traditional four-year colleges and universities.See the hardest schools to get into in America.