The Yerkes Observatory is located at 373 West Geneva Street in Williams Bay, Wis. The observatory is located near the shore of Geneva Lake, which is about halfway between Chicago and Milwaukee, due west from Kenosha. The GPS coordinates are latitude 42 34.2, longitude -88 33.4.
The Yerkes Observatory, a facility of the University of Chicago, is located on 77 acres at Geneva Lake. The site was established in 1897 and is considered to be the birthplace of modern astrophysics. The University of Chicago stopped holding all of its astrophysics courses on the Yerkes Observatory satellite campus in the 1970s.