In September of 1891, Pasadena philanthropist Amos G. Throop (pronounced Troop) established Throop University, the institution that would eventually become Caltech.
Throop University opened its doors with 31 students and a six-member faculty. Throop might have remained simply a good local school had it not been for the arrival in Pasadena of astronomer George Ellery Hale. The first director of the Mount Wilson Observatory, Hale became a member of Throop’s board of trustees in 1907 and began molding the school into a first-class institution for engineering and scientific research and education.
Hale would be joined later by chemist Arthur A. Noyes and physicist Robert A. Millikan. By 1920, the school was renamed the California Institute of Technology, and the enrollment was nine graduate students and 359 undergraduates, with a faculty of 60; a decade later there were 138 graduate students, 510 undergraduates, and a faculty of 180. At the present time there are nearly 1,000 undergraduates, 1,400 graduate students, and some 300 professorial faculty and more than 600 postdoctoral scholars.
Caltech has more than 24,000 living alumni all over the world, many of them eminent in their fields of engineering, science, law, medicine, academia, and entrepreneurship.
Caltech’s divisional structure, which began to coalesce in 1926, today comprises the Division of Biology and Biological Engineering (BBE); the Division of Chemistry and Chemical Engineering (CCE); the Division of Engineering and Applied Science (EAS); the Division of Geological and Planetary Sciences (GPS); the Division of the Humanities and Social Sciences (HSS); and the Division of Physics, Mathematics and Astronomy (PMA). To learn more about Caltech’s history and the people behind the Institute’s success, visit