As the tallest building and the center point of campus, Caltech Hall is named in honor of the Caltech community in its entirety. It houses the offices of Advancement and Alumni Relations and Technology Transfer and Corporate Partnerships, as well as other administrative offices and study spaces.

The building was named Caltech Hall in 2021. It was previously known as the Robert A. Millikan Memorial Library, named after Robert Andrews Millikan, director of the Norman Bridge Laboratory of Physics and chair of the Executive Council of the Institute from 1921 to 1945. The building was made possible by a gift from Seeley G. Mudd.

Caltech's Board of Trustees authorized the renaming following a unanimous recommendation by a committee charged to study Millikan and his affiliation with the eugenics movement.

Architect: Flewelling & Moody
Year occupied: 1967
Building number: 32
Building size: 61,574 gross square feet