In the 1890's Angel Island was used as a quarantine station for immigrants. If ships had any diseased passengers the entire ship would be fumigated with steam and sulfur dioxide. Immigration Station, as Angel Island was called in the early 1900's, was mainly used as a detention center for Asians coming into the United States. It was sometimes referred to as the Ellis Island (in New York harbor) of the west.

During World War II in the early 1940's Angel Island was used as a prisoner of war processing center for Germans and Japanese.