The Immigration Act of 1924 limited the number of immigrants allowed entry into the United States through a national origins quota. The quota provided immigration visas to two percent of the total number of people of each nationality in the United States as of the 1890 national census. It completely excluded immigrants from Asia. The immigration act made permanent the basic limitations on immigration into the United States established in 1921 and modified the National Origins Formula established then. In conjunction with the Immigration Act of 1917, it governed American immigration policy until the passage of the Immigration and Nationality Act of 1952, which revised it completely.
The act provided that no alien ineligible to become a citizen could be admitted to the United States as an immigrant. This was aimed primarily at Japanese aliens, but without explicitly naming them in the act.[18] It imposed fines on transportation companies who landed aliens in violation of U.S. immigration laws. It defined the term "immigrant" and designated all other alien entries into the United States as "non-immigrant", that is, temporary visitors. It established classes of admission for such non-immigrants.
