___ Island, locale in New York Harbor

ELLIS

This historic immigration station processed millions of newcomers to the U.S. in the late 19th and early 20th centuries.

This clue points to Ellis Island, the historic immigration station in New York Harbor where millions of immigrants arrived in the U.S. in the late 19th and early 20th centuries. The blank before "Island" signals you need a single word, and "Ellis" fits perfectly as the well-known name of the site. It’s a straightforward fill-in-the-blank with no wordplay—just a direct reference to a famous landmark.