Parsons-Gates is the home of Caltech's highest administrative offices, including those of the president and provost.

The second building on the early Caltech campus, it was constructed in 1917 and became the first unit of the Gates Laboratories of Chemistry, a gift of C. W. Gates and P. G. Gates. This first unit was retired after suffering extensive damage in the 1971 Sylmar earthquake but was rebuilt in 1983 as the Parsons-Gates Hall of Administration, with funds provided by the Ralph M. Parsons Foundation and the James Irvine Foundation.

Architect: Elmer Grey / Bertram Grosvenor Goodhue (1917 Gates Lab); Bobrow/Thomas & Associates (1983 remodel)
Year occupied: 1917 and 1983
Building number: 31
Building size: 28,517 gross square feet