* Yerkes Observatory (Wisconsin, USA): He was the director of the Yerkes Observatory from 1895 to 1904, where he helped establish it as a world-leading astronomical research center.
* Mount Wilson Observatory (California, USA): Hale was the driving force behind the establishment of the Mount Wilson Observatory in 1904, serving as its director until 1923. He oversaw the construction of the observatory's 100-inch Hooker telescope, the largest telescope in the world at the time.
* Palomar Observatory (California, USA): Hale initiated the planning for the Palomar Observatory, which would become home to the 200-inch Hale telescope, the world's largest telescope at the time. He passed away before the observatory's completion in 1948.
In addition to these major institutions, Hale also worked at the Kenwood Observatory and the University of Chicago.
His work across these institutions played a significant role in the development of modern astronomy and the advancement of telescope technology.