Ellis Island was the entry point for about 12 million immigrants to the United States between 1892 and 1954, the vast majority of coming between 1892 and 1924. While there were few national restrictions on immigration at the time, immigration from China was restricted by the 1882 Chinese Exclusion Act. In an overview of the history of immigration to the U.S. before 1965, history.com explains:
Between 1880 and 1920, a time of rapid industrialization and urbanization, America received more than 20 million immigrants. Beginning in the 1890s, the majority of arrivals were from Central, Eastern and Southern Europe. In that decade alone, some 600,000 Italians migrated to America, and by 1920 more than 4 million had entered the United States. Jews from Eastern Europe fleeing religious persecution also arrived in large numbers; over 2 million entered the United States between 1880 and 1920.
The peak year for admission of new immigrants was 1907, when approximately 1.3 million people entered the country legally. Within a decade, the outbreak of World War I (1914-1918) caused a decline in immigration. In 1917, Congress enacted legislation requiring immigrants over 16 to pass a literacy test [in English or in their native languages], and in the early 1920s immigration quotas were established. The Immigration Act of 1924 created a quota system that restricted entry to 2 percent of the total number of people of each nationality in America as of the 1890 national census–a system that favored immigrants from Western Europe–and prohibited immigrants from Asia.
The 28-minute film Island of Hope, Island of Tears provides a terrific overview of this history and the experience newcomers at Ellis Island.