The astrophysics program at the University of Chicago began with the building of the Yerkes Observatory, in Williams Bay, Wisconsin, where the entire Department was located. By the mid-sixties it had become clear that ties to the intellectual community on campus needed to be strengthened, and there was a shift of the center of mass from Wisconsin to Chicago. All of the academic programs are now on campus. Yerkes still provides laboratory facilities, contains the bulk of the library astronomy holdings outside of Crerar, and offers access to research telescopes and instruments for prototyping and instruction.