Final answer:
Ellis Island was the primary entry point for immigrants arriving on the East Coast, beginning operations in 1892 and admitting millions of people looking to start a new life in America.
Step-by-step explanation:
Immigrants arriving on the East Coast passed through Ellis Island before gaining entry into the United States. This island, located within the New York harbor, opened in 1892 and served as the primary port of entry for numerous immigrants until it closed in 1954. From 1900 to 1910, over nine million people entered the U.S., many of whom went through Ellis Island where they were subjected to inspection. Most of these immigrants were admitted with only a superficial check of their paperwork, except those presenting health issues or criminal history. Overall, Ellis Island represents a significant part of U.S. immigration history, with nearly half of Americans having ancestors who passed through its portals at some time.