The Immigration Act of 1924, also known as the Johnson-Reed Act, was a restrictive immigration law that limited the number of immigrants allowed into the United States: 

• Numerical limitsThe act established the first numerical limit on immigration to the U.S., setting a quota of 2% of the country-of-origin populations from the 1890 census. 
• National origin quotasThe act divided the global cap into national quotas for the Eastern Hemisphere, based on census data. 
• Exclusion of AsiansThe act barred immigrants who were “ineligible for citizenship,” effectively prohibiting immigration from Asian countries. 
• Border controlThe act authorized the creation of the U.S. Border Patrol, the country’s first formal border control service. 
• Consular control systemThe act established a “consular control system” that required immigrants to obtain a visa from a U.S. consulate abroad. 

The act was passed at the height of the eugenics movement and growing nativism following World War I. Its goals were to: Restrict immigration, Alter the demographic makeup of the United States, and Expand immigration and border enforcement globally. 

The act had a lasting impact on the U.S. population, reducing religious, ethnic, and racial diversity. It also shut out most European Jews and other refugees fleeing fascism and the Holocaust.